The Mummy's Club

Current medical guidelines recommend that babies swallow sucrose (sugar) solution before minor hospital procedures, such as the newborn heel prick blood test, as sugar solution is safe and effective at reducing pain they will feel.

The conclusions of this small study (44 babies analysed from 59 recruited for the study) directly challenge existing medical practice, with the finding that sugar did not reduce pain measured by looking at brain activity in response to a heel prick. Previous studies had all looked for a change in the baby’s facial expression to know when the baby was in pain, rather than looking directly at brain activity. This method of measuring pain in babies may be more objective than interpretations of facial expressions, but more research is needed to prove this.

The study itself did not find that using sugar was associated with any ‘damage to newborn brains’, instead it explained that pain itself may affect a developing brain. If the lack of effect of sugar is confirmed in larger studies, then it can no longer be thought of as an effective pain relief drug for small babies.

Where did the story come from?

The study was carried out by a researcher from the Nuffield Department of Anaesthetics at the University of Oxford, along with colleagues from University College London and Great Ormond Street Hospital for Children all in the UK. The study was supported by the Medical Research Council and published in the peer-reviewed medical journal The Lancet.

Several other newspapers including the Mail and the Mirror also covered this story and reported it fairly. They focused on the fact that pain may cause short or long-term adverse effects on the development of the infant brain and suggested that if sugar is merely a distraction, then hugs or breastfeeding may work just as well.

What kind of research was this?

All babies have a heel prick blood test before they are eight days old to test for a variety of conditions. Currently, it is recommended that babies swallow sucrose (sugar) solution before the test to reduce any pain they may feel. Previous studies, including a systematic review of 44 studies, have suggested that sugar solution is safe and effective for reducing pain from minor hospital procedures.

In this double-blind, randomised controlled trial, the researchers wanted to find out if the sugar solution was actually reducing pain in the babies. The researchers explain that trials of pain relief in small babies are a challenge as the usual ways of reporting pain in clinical trials, such as asking for a description of the pain or using pain relief charts, cannot be used in babies. Usually in studies with babies, an observational pain score (premature infant pain profile – PIPP) is used. This combines video recordings made of the babies facial expressions (grimacing), as well as behavioural and physiological measures, such as oxygen use.

This study used an electroencephalography (EEG) cap to measure the electrical activity in the brain in response to pain as well as the usual PIPP response. The researchers monitored the brain activity of the babies during the heel prick test to look for a particular pattern of pain-specific brain activity, to see if the sugar solution caused a reduction in the pain response.

Care was taken to ensure no one involved in the study knew which babies had received which intervention.

What did the research involve?

The researchers carried out their study from February 2009 to March 2010. The participants were all healthy newborn infants born at 37-43 weeks of pregnancy and were less than eight days old when tested.

The researchers excluded babies from the study if they showed signs of tissue damage on the lower limbs, had previous surgery, serious illness or were born to diabetic mothers or opioid users. The babies were randomly assigned to receive either 0.5mL of 24% of sucrose solution or an equivalent volume of sterile water on the tongue.

A non-painful control stimulus was used first in all babies. The heel prick device was placed on the heel but the blade did not puncture the skin. The solution was then placed on the tongue two minutes before the actual heel prick took place.

Recording electrodes were positioned on the scalp to record the EEG, using the EEG cap. The researchers also used videos to record the behaviour and the facial expressions of the infants along with heart rate and oxygen levels in the blood and reflex movements of the limbs during the heel prick.

The researchers analysed the results on 20 out of 29 from the sucrose group and 24 out of 30 allocated to the sterile water group. The dropouts were mainly due to technical failure of the EEG, for example because of excessive movement. Only one parent withdrew consent in the sterile water group.

What were the basic results?

The measure of brain activity after the painful heel prick did not differ significantly between infants who received sucrose: mean 0.1 (95% Confidence Interval [CI] 0.04 to 0.16) compared with those who received sterile water: mean 0.08 (95% CI 0.04 to 0.12) p=0.46.

The PIPP score, a combined measure of heart rate, oxygen levels and facial expression (grimacing) scored from the video, was significantly lower in infants given sucrose compared with those given sterile water. Furthermore, significantly more infants had no change in facial expression after sucrose administration; 7 of 20 given sterile water (35%) compared with none of 24 given sucrose (p<0.0001).

How did the researchers interpret the results?

The researchers say that oral sucrose does not significantly affect activity in neonatal brain or spinal cord pain circuits, and therefore might not be an effective pain reliever.

They say that the ability of sucrose to reduce the PIPP scores observed in newborn infants after a painful event should not be interpreted as pain relief.

Conclusion

This study has used objective measures of pain in a small sample of infants and used careful blinding and randomisation to reduce bias. There are a few limitations due to the study size, but the conclusions are likely to challenge the currently held belief that sugar is an effective treatment for the pain of minor procedures in infants. The limitations mentioned by the researchers were:

• The small sample size of 44 infants analysed, which could mean that this study was not powered to observe subtle effects that sucrose might have on the brain processes used for pain.
• A measure of pain in infants is necessarily indirect (because they cannot describe the sensation), and so even though the electrophysiological measures reported in this study are more objective it is not clear that they are measuring the conscious pain experience of the newborn infant.
• The significant reduction of PIPP scores with sucrose confirm the results of the systematic review that looked at this as their main outcome.
• The drop out of 15 infants (25% of those recruited) may have affected the reliability of the results.

The study itself had not identified harms associated with the use of sugar and it is an extrapolation to suggest that the use of sucrose for newborn pain relief ‘may damage their brains’. This may be particularly alarming for parents or doctors to read and is not a finding of this study. There is growing evidence that some newborns’ experience of pain may have lasting adverse effects on their neurodevelopment but to state this in a way that suggests that a study has shown that using sugar causes damage to newborn brains is unhelpful.

The researchers suggest that this single-centre trial should be repeated in a larger sample of infants, and that the new EEG measurement method should be used to test the effect of other known pharmacological analgesic drugs, such as morphine. This seems like sensible advice.

Links To The Headlines

Newborn babies should not be given sugar as pain relief, says study. The Guardian, September 2 2010

Pain relief is not so sweet for babies. Daily Mirror, September 2 2010

A hug, the sugar-free way to ease baby’s pain. Daily Mail, September 2 2010

Links To Science

Slater R, Cornelissen L, Fabrizi L et al. Oral sucrose as an analgesic drug for procedural pain in newborn infants: a randomised controlled trial. The Lancet, [Early Online Publication] September 1 2010

Stevens B, Yamada J, Ohlsson A. Sucrose for analgesia in newborn infants undergoing painful procedures. Cochrane Database of Systematic Reviews 2010, Issue 1

Shah PS, Aliwalas LL, Shah VS. Breastfeeding or breast milk for procedural pain in neonates. Cochrane Database of Systematic Reviews 2006, Issue 3

This news story is based on a small study that looked at brain structure in 14 men and 28 women, half of whom were using hormonal contraception. It found that certain areas of grey matter in the brain were larger in women taking hormonal contraceptives than in women not using hormones, and in women in their early phase of their menstrual cycle compared to later in the cycle. The researchers say that this shows that both these factors can affect the human brain structure.

However, this study is too small to conclude that the Pill or the menstrual cycle affects the volume of grey matter in the brain. There is no way of knowing what other factors, including genetic factors, may have had an effect on these participants’ brains as no other data was taken. Also, since it did not actually examine or measure cognitive performance, it cannot shed any light on how the Pill might affect cognitive or social skills.

Where did the story come from?

The study was carried out by researchers from the Paris Lodron University of Salzburg and Paracelsus Private Medical University of Salzburg. It was funded by the Austrian Academy of Science. The research was published in the peer-reviewed journal Brain Research.

The Mail’s report, which included claims that the Pill “enhances the brain’s conversation hub”, exaggerated the significance of the study. There is no basis in the study for the newspaper’s claim that the Pill makes women brainier, nor for a similar report in the Telegraph that it improves memory and social skills.

What kind of research was this?

The researchers say that differences between the brain structure of men and women have been investigated many times. These studies have suggested that the amount of grey matter in particular parts of the brain differs between the sexes, but so far these differences have been inconsistent between studies. The researchers suggest that these inconsistencies may be due to hormonal fluctuations during the menstrual cycle or women’s use of hormonal contraceptives. They point out that most previous studies have not taken into account the effect of hormones.

This experimental study investigated possible differences in human brain structure between men and women at different phases of the menstrual cycle, and women using the contraceptive pill. They did this by measuring the volume of grey matter in their brains using an MRI scan. No direct measurements of cognitive abilities such as memory, navigation or social skills were taken.

What did the research involve?

The scientists used an MRI scanner to take high-resolution images of the brain structures of 14 healthy men and 28 healthy women, all in their early to mid-twenties. Half of the women were using the Pill, although the type, brand and dose was not recorded. Women who were not using the Pill were scanned twice, once during the early follicular part of the menstrual cycle, and once during the middle (or mid-luteal) phase.

All participants were not taking any other medications and had no history of any disorders that might affect brain structure or function. The women not using hormonal contraception had regular menstrual cycles and had not been diagnosed with any menstrual disorders.

Using the scans, the types of brain tissue were classified and the volume of various regions were measured. An analysis that compared the results between the three different groups was carried out.

What were the basic results?

The results were analysed according to gender, phase of cycle and use of hormonal contraception. Overall, men and women had differences in the volume of grey matter in different parts of the brain. In regions where women had larger volumes than men, this difference in size was more pronounced during the early part of the menstrual cycle (in naturally cycling women) and in women using hormonal contraception.

Gender-dependent effects

• Men had a larger volume of grey matter in certain parts of the brain than both groups of women, especially compared to “naturally cycling” women in the phase when hormone levels are low.
• Both groups of women had larger volumes in other regions of the brain, with the effect being most pronounced in hormonal contraceptive users.
• The grey matter volume in the cerebellum (the region just above the brain stem that has an important role in motor control), was larger in men than naturally cycling women, but larger in women on hormonal contraception than in men.

Cycle-dependent effects

• Naturally cycling women had significantly more grey matter in certain regions during the early phase of the cycle than in the later phase.

Effects of hormonal contraceptives

• Women using hormonal contraception showed more grey matter in certain regions of the brain than naturally cycling women during both cycle phases.

How did the researchers interpret the results?

The researchers conclude that sex hormones have a “tremendous effect” on brain structure, as demonstrated by differences between hormonal contraceptive users and naturally cycling women in the amount of grey matter in certain regions. In regions that were already larger in women compared to men, using hormones was associated with an even larger volume of grey matter. In men, the regions with more grey matter were hardly affected by contraceptive use.

The researchers say this finding could be related to earlier suggestions that the menstrual cycle affects performance variations in memory and sex differences in “navigation abilities”.

Conclusion

This small study seems to show that in certain regions of the brain, women using hormonal contraception had larger GM volume than naturally cycling women. The researchers suggest that this may be due to differences in hormone levels, specifically “enhanced” oestrogen and/or progesterone levels. They conclude that more clarification is needed on the specific roles of oestrogen and progesterone.

While this small study is interesting, it is too small to draw any conclusions about the differences in brain structure between men and women, and between women taking the Pill and those who are not. It did not take into account any other factor that might affect brain structure (other than ensuring the absence of disease in participants). In the naturally cycling group, it also relies on women self-reporting the stages of their cycle, which introduces the possibility of error.

It is important to emphasise that the study did not measure the participants’ cognitive function, so no conclusions can be drawn from this study about the effects of hormonal contraception on cognitive abilities or skills.

Links To The Headlines

The Pill makes you brainier: It can swell grey matter essential for social skills and memory, say scientists. Daily Mail, August 18 2010

Contraceptive pill ‘increases brain size and function’. The Daily Telegraph, August 18 2010

Links To Science

Pletzer B, Kronbichler M, Aichhorn M et al. Menstrual cycle and hormonal contraceptive use modulate human brain structure. Brain Research 2010: 1348; 55-62

The study followed 482 individuals from birth until their mid thirties, and this unusually long follow-up time is one of the study’s strengths. The main limitation of this study is that many unmeasured factors may influence a person’s adult wellbeing, for example paternal affection as a child, or health or work status as an adult. It is also important to note that the adults in this study were, on average, in the normal range of emotional functioning.

It is likely that a complex mix of factors influences our adult wellbeing, and it seems plausible that our childhood experiences could be among them. However, the interactions between these numerous factors mean that teasing out the effects of individual factors is likely to be difficult and that maternal affection may not necessarily be the principal factor behind mental resilience.

Where did the story come from?

The study was carried out by researchers from Duke University, Harvard School of Public Health and Brown University in the US. One of its authors received partial funding from the US National Institutes of Mental Health. The study was published in the peer-reviewed Journal of Epidemiology and Community Health.

The Daily Mail and BBC News have reported on this research. The Daily Mail points out a strength of the study, saying that “most previous studies have relied on people’s recollections – whereas this research tracked participants from early childhood to adult life”. The BBC also makes the important point that “the influence of other factors, such as personality, upbringing and schooling, could not be ruled out”.

What kind of research was this?

This was a prospective cohort study that looked at the association between maternal affection early in a child’s life and their emotional functioning as an adult.

The researchers looked at children who had originally been part of the National Collaborative Perinatal Project (NCPP), which had enrolled their mothers during pregnancy from 1959 to 1966. At the age of eight months, the interaction of mothers with their children was observed and rated according to how affectionate it was. The emotional functioning of the offspring was assessed when they became adults. The researchers then looked to see whether there were relationships between a mother’s level of affection at eight months and adult emotional functioning.

What did the research involve?

An evaluation of maternal affection was made by a psychologist while the mother and baby attended cognitive and developmental testing as part of the NCPP study. Levels of affection were rated as: “negative” or “occasionally negative” (both indicating a low level of affection), “warm” (indicating normal affection), and “caressing” or “extravagant” (both indicating a high level of affection). For the current analyses the “negative”, “occasionally negative” and “warm” groups were pooled, while “caressing” and “extravagant” were pooled into a high affection group.

A sample of 1,062 NCPP offspring were contacted in 1996, when they were on average 34 years old. Of these individuals, 482 agreed to participate and had complete data available for analyses. Emotional functioning was assessed using a standard symptom checklist (Symptom Checklist-90, SCL-90). This checklist includes an assessment of four common types of distress, including distress due to:

• somatisation: psychological distress manifesting itself through physical symptoms
• interpersonal sensitivity: the extent to which an individual can recognise or understand another’s emotions or feelings
• anxiety
• hostility/anger

An overall distress score was calculated based on these four types of distress. These scores were calculated in such a way that they ranged from 0 to 100, where the average score in a normal population would be 50, and a normal range considered to be 40 to 60.

The researchers took into account factors that could influence the analysis, including parental socio-economic status and maternal history of mental illness (based on self-report), which were assessed as part of the NCPP. They also took into account age, race, high-school completion and marital status of the adult offspring.

What were the basic results?

Approximately 10% of mothers displayed a low level of affection for their child at the age of eight months, 85% showed a normal level of affection and 6% showed a high level of affection.

Participants whose mothers showed a high level of affection to them at the age of eight months showed lower levels of overall distress as adults than those whose mothers showed normal or low levels of affection. The high-affection group had an overall average distress score of 50.39 and the low/normal affection group an overall average distress score of 55.38. When looking at the specific areas of distress, the relationship was strongest in the area of anxiety, where the high and low/normal groups differed by 7.15 points, and least strong in the area of hostility, where the high and low/normal groups differed by 3.29 points.

How did the researchers interpret the results?

The researchers concluded that “early nurturing and warmth have long-lasting positive effects on mental health well into adulthood”.

Conclusion

This study’s findings suggest that maternal affection early in life may influence adult distress levels. Strengths of this research include assessment of maternal affection by an independent observer and the following-up of participants from childhood into adulthood. However, there are some limitations:

• Only a subset of children from the original study was followed up. Inclusion of all of the children might have influenced the results if the children who did not participate differed from those who did.
• There may be factors other than maternal affection that are influencing results. Although the researchers took some of these into account, there are many others that may be having an effect, including paternal affection or general family affection as a child, or health and work conditions as an adult.
• Although maternal affection was rated by independent observers, the ratings of affection are likely still to be subjective to some extent (for example, what one observer considered negative might be normal to another observer). The researchers attempted to counteract this by providing extensive training for the assessors and carrying out quality control across the study sites.
• Maternal affection was only assessed on one occasion (at the age of eight months), and may not be representative of overall maternal affection throughout childhood.
• It is also important to note that both groups of adults (those receiving low/normal and those receiving high levels of affection as babies) had distress scores within the normal range.

There are likely to be many factors influencing our adult wellbeing, and it seems plausible that this could include our childhood experiences. However, the number of factors and the possible interactions between these factors means that teasing out the effects of individual factors is likely to be difficult.

Links To The Headlines

Maternal love helps you deal better with stress and anxiety later in life. Daily Mail, July 27 2010

Motherly love ‘does breed confidence’. BBC News, July 27 2010

Links To Science

Maselko J, Kubzansky L, Lipsitt L,  Buka SL. Mother’s affection at 8 months predicts emotional distress in adulthood. Journal of Epidemiology and Community Health 2010; Published Online First July 26 2010

The importance of the guidelines is borne out by figures suggesting that more pregnant women than ever are overweight or obese. The Guardian suggests that, “15-20% of women getting pregnant are overweight or obese”. The Daily Mail puts the number higher, saying that “almost half of expectant mothers are overweight or obese”. It goes on to spell out the dangers of being obese or overweight during pregnancy, which include “fatal health conditions such as blood clots, pre-eclampsia, miscarriages and stillbirths”.

The newspapers also dispel the myth that women should eat for two during pregnancy. Further advice reported in the press includes taking at least 30 minutes of moderate exercise per day during pregnancy, and that pregnant women should avoid dieting and only need to have an extra 200 calories a day in the last three months of their pregnancy.

These guidelines are published by NICE, and are evidence-based. They are designed so that doctors can give women up-to-date reliable advice to follow to maintain a healthy weight before, during and after their pregnancy.

Where did the advice come from?

The advice has just been published by the National Institute for Health and Clinical Excellence (NICE) as part of its public health programme. NICE produces guidance on the promotion of good health and the prevention of ill health for those working in the NHS, local authorities and the wider public and voluntary sector.

What are the health risks of being obese during pregnancy?

Women who are obese (with a BMI over 30) when they become pregnant face an increased risk of complications such as diabetes, miscarriage, pre-eclampsia, blood clots and death. Obese women are also more likely to have an induced or longer labour, post-delivery bleeding and slower wound healing after delivery. They also tend to be less mobile, which can result in a need for more pain-relieving drugs during labour. These can be difficult to administer in obese women, resulting in a greater need for general anaesthesia with its associated risks.

For women who have gained weight between pregnancies, even a relatively small gain of 1-2 BMI units can increase the risk of high blood pressure or diabetes during their next pregnancy and may also increase the chance of giving birth to a large baby.

What sort of diet does NICE recommend?

NICE offers the following dietary advice to help women to achieve and maintain a healthy weight:

• Base meals on starchy foods (such as potatoes, bread, rice and pasta), choosing wholegrain where possible.
• Eat foods rich in fibre.
• Eat at least five portions of fruit and vegetables per day in place of foods higher in fat or calories.
• Eat as little as possible of fried foods, and drinks and confectionery high in sugars and fats.
• Eat breakfast.
• Watch portion size of meals and how often they are eaten.

What should women aim to weigh before getting pregnant?

Women with a BMI of 30 or more can achieve significant health benefits if they lose between 5-10% of their weight. Further weight loss to achieve a BMI within the healthy range of 18.5 and 24.9 is encouraged.

What about weight during pregnancy?

The amount of weight a woman may gain in pregnancy varies a great deal, and only some of it is due to increased body fat. The unborn child, placenta, amniotic fluid and increases in maternal blood and fluid volume all contribute to weight gain during pregnancy.

• Dieting during pregnancy is not recommended as it may harm the health of the child.
• There is no need to ‘eat for two’ or drink full-fat milk (as opposed to lower-fat milk). Energy needs do not change in the first six months of pregnancy. Only in the last three months do a woman’s energy needs increase by around 200 calories per day.
• Moderate-intensity physical activity will not harm the mother or baby. At least 30 minutes per day of moderate intensity activity is recommended. This can include activities such as swimming or brisk walking. If women have not exercised routinely up to that point, they should begin with no more than three 15-minute sessions a week, increasing gradually to daily 30-minute sessions.
• There are no formal evidence-based guidelines from the UK Government or professional bodies on what constitutes appropriate weight gain during pregnancy.

How do I safely lose weight after giving birth?

Women are encouraged to breastfeed, but are advised against dieting while breastfeeding. Women who feed their babies with breastmilk only for the first six months may require an additional 330 calories a day, but this may differ between individuals, and some of these additional calories will be derived from fat stores built up during pregnancy.

If the pregnancy and delivery are uncomplicated, mothers may start a mild exercise programme consisting of walking, pelvic floor exercises and stretching immediately after giving birth, but women should not resume high-impact activity too soon. Women who have had complicated deliveries or caesareans should not resume pre-pregnancy levels of physical activity before consulting their medical caregiver.

Health professionals should be able to provide details of appropriate community-based services for women who want support to lose weight.

Where can I get more information?

Women should consult their GP or midwife about maintaining a healthy lifestyle before, after and during their pregnancy.

Links To The Headlines

Mothers must lose baby weight before getting pregnant again, NICE says. The Daily Telegraph, July 28 2010

Weight, exercise and pregnancy confusion. BBC News, July 28 2010

Mothers who lose weight before further pregnancy ‘reduce risks’. The Guardian, July 28 2010

Don’t eat for two, pregnant mothers are told amid obesity fears. Daily Mail, July 28 2010

In the study researchers recorded the speech of three groups of children aged 10-48 months: 106 ‘typically-developing’ young children, 49 children with language delay and 77 children diagnosed with autism. Their fully automated recording devices were able to determine differences in speech between the groups and accurately predict which children were from each group. The technique also follows the child in their natural home setting, providing the opportunity for efficient and effective speech assessment in a familiar environment.

This research is still in the early stages, and further study will determine how this system could work alongside other developmental assessment methods. So far, the system has not been investigated as a method for diagnosing new cases of language or developmental delay. Before it is introduced into practice, the uses and feasibility of this novel approach will need to be explored.

Where did the story come from?

The study was carried out by researchers from the Universities of Memphis, Chicago and Kansas and was funded by the Plough Foundation at the University of Memphis. It was published in the peer-reviewed scientific journal Proceedings of the National Academy of Sciences USA.

What kind of research was this?

This was an observational study that attempted to further the techniques used in researching speech and language development. The aim was to investigate an automated method for assessing young children’s speech development on a large scale by carrying out extended recordings in the homes of infants and young children. The main goal of the research was to isolate each child’s vocalisations from other voices and background noise on candid recordings and automatically identify significant features that could be useful predictors of the child’s developmental level.

What did the research involve?

To gather audio samples, the researchers provided parents with a battery-powered recorder that was then attached to their child’s clothing, recording the child in their natural environment all day. The children recorded were drawn from three different groups: those whose parents self-reported them to be typically-developing, those reported to have language delay and those reported to have autism.

Language delay was confirmed by checking for documentation in medical records or by assessment with a speech and language clinician, and autism was confirmed by checking medical records of the diagnosis. The final sample recorded featured a total of 232 children:

• 106 ‘typically-developing’ children aged 10-48 months
• 49 children with language delay aged 10-44 months
• 77 children with autism aged 16-48 months

The researchers carried out a total of 1,486 all-day recordings across the groups over the three years of the study, which provided a total of 23,716 hours of audio and captured a total of 3.1 million child utterances.

The recording devices were able reliably to differentiate between the child’s vocalisations and other sounds, allowing the researchers to carry out an in-depth analysis of the 12 parameters of speech known to have a role in speech development. These parameters included how the child was able to articulate each syllable, speech rhythm, pitch, their vocal characteristics and duration of speech.

The researchers looked at the relationship between a child’s overall vocalisations and the number of the 12 parameters that were as expected according to their age.

What were the basic results?

The researchers found that the automated analysis was able to predict development.

• In the typically-developing group all 12 of the parameters of speech were as expected according to their age.
• In the language-delayed group 7 of 12 parameters were as expected for their age.
• In the autism group few of the 12 parameters of speech were as expected according to age.

The study also found that in the typically-developing group certain vocal tendencies diminished with age, while this was not seen in the other groups. They also noted that children with autism tended to have quite unpredictable patterns of development, suggesting that they had different vocalisation from both typically-developing children and those with language delay.

Overall, the test correctly identified 90% of children who were in the ‘typically-developing’ group, 80% of those with autism and 62% of those with language delay.

How did the researchers interpret the results?

The researchers considered this research to be a ‘proof of concept’, a type of developmental project designed to test how well a conceptual method translates into real-world use. They demonstrated that their method of automated assessment was able to track children’s development on acoustic parameters known to play key roles in speech, and was also able to differentiate the vocalisations of children with autism or language delay from those of typically-developing children.

They conclude that their study of ‘automated analysis’ has the potential to advance research in speech and language development.

Conclusion

This was valuable research that has carried out extensive all-day recordings of children and found that the automated analyses of their vocalisations could distinguish between children with normal development, language delay and autism.

The advantage of this method is that it is completely automated, requiring no human intervention. As it follows the child in their home, it provides the opportunity for efficient and effective speech assessment in a familiar environment.

This research is still in the developmental stages. Further study will be needed to see how this recording system could supplement developmental assessment of children by health professionals and the standard screening and diagnostic procedures used.

So far, the system has only been used to detect previously-diagnosed conditions, and has not yet been tested as a means of identifying undiagnosed linguistic or developmental delay. This means the accuracy of the test needs further testing. Additionally, there are likely to be many other considerations to be addressed before this could be brought into practice, including the costs and feasibility of distributing recorders on a large scale and then having trained personnel available to interpret the data from these in-depth recordings.

As the researchers say, the ability to study linguistic development in natural home environments could provide a completely objective way of detecting speech-related disorders in early childhood. Such an advance would be a highly valuable medical tool for speech and language therapists.

Links To The Headlines

Autism detected in voice of children. The Daily Telegraph, July 20 2010

Speech pattern can give early clue to autism. The Independent, July 20 2010

Voice technology ‘could help detect autism’. BBC News, July 20 2010

Links To Science

Ollera DK, Niyogic P, Gray S et al. Automated vocal analysis of naturalistic recordings from children with autism, language delay, and typical development. PNAS, July 20 2010

The well-conducted study behind the story reviewed records of over one million full-term, single baby births in Scotland from 1985 to 2004. It found an increased risk of newborn death out of hours (i.e. during the night time and weekends), with deaths mostly related to lack of oxygen during delivery. However, these results must be interpreted in the correct context, as the risk of newborn death was very low in both groups: 4.2 out of 10,000 births in normal working hours, and 5.6 out 10,000 births out of hours.

As the researchers say, the observations could be due to many different causes, as the reasons behind this relationship were not examined and should not be assumed to be due to ‘hospital staffing shortages’. Many women deliver out-of-hours (three-quarters in this sample) and research will continue to examine the link between time of birth and adverse outcomes for mothers and babies.

Where did the story come from?

The study was carried out by researchers from University of Cambridge and University of Glasgow, and was funded by Medical Research Council and the Royal College of Obstetricians and Gynaecologists. The study was published in the peer-reviewed British Medical Journal.

The papers have reflected the findings of this research, but in general fail to clarify that the risk of death was small for both day and night births. It is misleading to report that the associations may be ‘due to hospital staffing shortages’, as the causes of different death rates have not been examined in this research and any such claims are based on speculation.

What kind of research was this?

This was a population-based cohort study that examined data from Scottish birth certificates and relevant databases between 1985 and 2004. It aimed to assess whether the time and day of birth had an effect upon the risk of newborn death. This particular study has the advantages of having access to a large quantity of data covering over one million births. However, it does rely on records being filled in accurately and completely.

The study did not assess the reasons behind any observed associations between time of birth and mortality risk, which could be due to a number of factors. As such, it should not be assumed that this is due to lack of skilled staff being available out of hours.

What did the research involve?

The researchers used various data sources. The Scottish Morbidity Record collects information on the outcomes for mothers and babies discharged from Scottish maternity hospitals. This record was used to identify all single-baby births between 1985 and 2004. The babies were linked to the Scottish Stillbirth and Infant Death Survey, which uses codes to record the cause of death for all babies who die around the time of birth.

The researchers were only interested in single babies born at term (between 37 and 42 weeks), with no congenital abnormalities, who were ‘cephalic’ (presenting head first) at full-term, and for whom the delivery method was recorded. They also performed a separate analysis only looking at babies who were delivered at hospital units that delivered more than 10 babies a year.

The main outcome of interest was death in the newborn, defined as death of a liveborn baby within the first four weeks of its life. The grouped births based on their day and time of delivery:

• Weekday births: between 09:00 and 1700 Monday to Friday
• Overnight weekday births: between 17:01 and 08:59 on weekday nights (includes Saturday  morning until 08:59)
• Weekend births: from 09:00 on Saturday mornings until 08:59 on Mondays
• All out-of-hours births: collectively, all births at any time other than 0900-1700, Monday to Friday

The association between risk of death and time of birth was adjusted for various possible confounding factors, including characteristics of the birth, maternal characteristics and obstetric history, social and demographic characteristics, and ‘hospital throughput’ (total number of births for a given hospital in a given year).

What were the basic results?

A total of 1,039,560 live births met the specified inclusion criteria, which corresponded to over 95% of all single full-term births in Scotland for 1985-2004. Within the study cohort, 72% of births occurred out-of-hours. In total there were 539 (0.05%) newborn deaths, which was equivalent to a rate of 5.2 out of 10,000 live births. Analysis revealed that just over half of these births (273) were related to anoxia (lack of oxygen) during delivery.

During normal weekday working hours (Monday to Friday, 0900-1700) the risk of newborn death was 4.2 out of 10,000, and for all other times (out-of-hours) it was 5.6 out of 10,000: equivalent to a 30% greater incidence of death (odds ratio 1.3, 95% confidence interval 1.1 to 1.6).

They found that the increased chance of death out-of-hours was mostly related to a higher number of deaths due to anoxia (70% increased risk of death due to anoxia [a total decrease in the level of oxygen] out of hours; odds ratio 1.7, 95% CI 1.2 to 2.3). The attributable fraction of newborn deaths ascribed to anoxia during delivery out-of-hours was 26% (that is 26% of deaths related to anoxia during birth might not occur if women could deliver during normal hours rather than out-of-hours).

The associations seen were not due to confounding by maternal, infant and obstetric characteristics.

How did the researchers interpret the results?

The researchers conclude that delivery of an infant outside of the normal working week was associated with an increased risk of newborn death due to anoxia during delivery.

Conclusion

This is a well-conducted study that has analysed Scottish medical records on over one million single, full-term births to determine whether there were any association between time of birth and risk of newborn death. A particular strength of this study is the accuracy of the records used: the Scottish morbidity record reportedly has an almost 99% completion since the late 1970’s and receives regular quality assurance checks; the Stillbirth and Infant Death Survey is completed using the General Register Office, and is reportedly 100% complete.

Though there was an increased risk of newborn death out-of-hours, mostly related to deaths due to lack of oxygen during delivery, these results must be interpreted in the appropriate context:

• The risk of newborn death, regardless of birth time, is very low. The rate in this large population study was 4.2 out of 10,000 during normal working hours, increasing to 5.6 per 10,000 out-of-hours. Therefore, although this relates to a 30% increased risk, the actual number of deaths for out-of-hours births is still very small.
• The reasons for the observations, particularly the excess deaths due to anoxia, cannot be easily explained as the situations surrounding the adverse birth outcomes were not examined in detail.
• As the researchers say, there are many possible reasons for the deaths, which may or may not be due to the variation in staffing availability at different times of the day or fewer clinical facilities available out-of-hours. However, they caution that this cannot be assumed.

Many women deliver out-of-hours (almost three-quarters of this cohort) and this is not something that can easily be controlled. A number of studies have examined the relationship between time of birth and adverse outcomes for the mother or baby, finding similar associations in some cases but no association in others. Research in this area is likely to continue, with the hope of possibly identifying any interventions that could reduce any discrepancy in outcomes between births during the normal working week, and those occurring at night or over the weekend.

Links To The Headlines

Babies born outside working hours are ‘more likely to die’. The Daily Telegraph, July 16 2010

Babies born at night three times more at risk of death. Daily Mail, July 16 2010

Out-of-hours births ‘are riskier’. BBC News, July 16 2010

100 out-of-hours babies die a year. The Sun, July 16 2010

Links To Science

Pasupathy D, Wood AM, Pell JP et al. Time of birth and risk of neonatal death at term: retrospective cohort study. BMJ 2010;341:c3498

This news story was based on laboratory research looking at the role of a gene called C35 in breast cancer cells. The researchers were interested in C35 as 40-50% of breast tumours produce excess amounts of C35 protein. They found that cells producing excess amount of C35 in the laboratory take on the characteristics of cancerous cells, for example, being able to spread. The study carried out preliminary tests that found that certain chemicals could stop C35 causing some of these changes occurring in laboratory grown cells. Much more research will be needed to determine whether these chemicals might be safe and effective for testing in humans.

This research contributes to our knowledge of which genes play a role in the development of breast cancer. Such advances are important for identifying possible targets for new drug development. However, it is unfortunately much too early to say that we have a new drug for stopping the spread of breast cancer.

Where did the story come from?

The study was carried out by researchers from the University of Edinburgh and other research centres in the UK and US. It was funded by the Scottish Funding Council and Breakthrough Breast Cancer. Two of the authors work for a company called Vaccinex Inc, which discovered that C35 was a biomarker for breast cancer. The study was published in the peer-reviewed British Journal of Cancer.

The Daily Express, Daily Telegraph, and BBC News cover this story. The Express and Telegraph headlines highlight the possibility of a new drug, with the Express headline implying that the drug already exists. This claim is not supported by the current research, which solely investigated the role of a gene called C35 in breast cancer cells, but did not develop or test a ‘new drug’ to target it. The BBC News headline better reflected the findings of the research, noting that a gene involved in the spread of cancer has been found.

What kind of research was this?

This laboratory study investigated the role of a gene called C35 in breast cancer. In about a fifth of breast cancers the tumour cells have undergone a genetic mutation which results in the cell carrying multiple copies of a piece of DNA which carries the HER2 gene as well as other genes, including C35. Tumours carrying this mutation (called HER2 positive tumours) tend to be more aggressive than those that do not. This is at least in part because the cells are producing too much HER2, but could also be due to them producing more of the proteins encoded by other copied genes such as C35. The researchers wanted to investigate whether this was the case, particularly as about 40-50% of breast cancers are reported to produce excess amounts of the C35 protein.

Laboratory research is essential to furthering our knowledge of how cells become cancerous. Such knowledge can help to identify targets for new drug treatments.

What did the research involve?

The researchers used tissue samples from 122 primary breast cancers and examined whether the cells producing excess HER2 protein also produced excess C35 protein. They also took some normal breast tissue cells and genetically engineered them to produce excess C35 protein to see what happened. Finally, they looked at whether a protein called Syk which they thought might be involved was needed for C35 to have an effect. They did this by looking at whether blocking Syk with two chemicals called BAY61-3606 and piceatannol stopped C35 from having an effect on the genetically engineered cells.

What were the basic results?

The researchers found that breast cancer tissue that produced excess HER2 protein also tended to produce more C35 protein.

Normal breast tissue cells that were genetically engineered to produce excess amounts of C35 protein took on some of the characteristics of cancer cells. This included forming clumps of ‘colonies’ when grown in a soft gel in the laboratory, and spreading through such gels. The cells also lost their typical characteristics and took on the characteristics of less specialised, more immature cells; another characteristic typical of cancer cells. Further investigation showed a protein called Syk was involved in allowing C35 to have these effects. Blocking the action of Syk using the chemicals BAY61-3606 or piceatannol also blocked some of the effects of C35.

How did the researchers interpret the results?

The researchers conclude that ‘amplifying’ the C35 gene can promote a normal cell to develop the characteristics? of a cancer cell (that it, it acts as an “oncogene”) in breast cells grown in the laboratory. They suggest that drugs targeting C35 or Syk “might be helpful in treating a subset of patients with HER2-amplified breast cancers”.

Conclusion

This research contributes to our knowledge of which genes play a role in the development of cancer. Such advances are important for identifying possible targets for new drug development. Although the researchers did illustrate that chemicals known to inhibit the activity of Syk can reduce the effect of C35, much more research will be needed to determine whether these chemicals might be appropriate for use in humans.

The path to developing a new drug for use in humans is a long one and designed to be as certain as possible that the drug will be effective and safe. Therefore, even if these chemicals are successful in the laboratory, they will also have to be tested on animals before they can be tested on humans. It is much too early for newspapers to report of a new drug that stops the spread of breast cancer, but research such as this will hopefully yield new treatments in the long term.

Links To The Headlines

New drug stops deadly spread of breast cancer. Daily Express, July 14 2010

Hope of new treatment for aggressive breast cancer. The Daily Telegraph, July 14 2010

Discovery of gene in aggressive spread of cancer. BBC News, July 14 2010

Links To Science

Katz E, Dubois-Marshall S, Sims AH, et al. A gene on the HER2 amplicon, C35, is an oncogene in breast cancer whose actions are prevented by inhibition of Syk. British Journal of Cancer 2010; July 13

This news is based on research that looked at records of babies born to mothers aged between 14 and 29 in the North West of England. The study found that teenage mothers aged 14 to 17 were more likely to have preterm babies than older mothers, with the risk being greater for teenagers who had their second child before the age of 17. Teenagers’ babies were also smaller on average than the babies of older mothers, with first babies being on average 24g lighter and second babies being on average 80g lighter.

Associations between teenage pregnancy and the adverse outcomes of premature birth and lower birthweight have been observed for some time. However, even with the evidence from this study, the reasons why are unclear and theories explaining these associations remain unproven. Further research is now needed to assess whether this effect is due to the physical immaturity of teenage mothers or differences in their lifestyle and diet that affect the pregnancy.

Where did the story come from?

The study was carried out by researchers from the University of Cork and the University of Manchester, and was funded by the Health Research Board of Ireland. The study was published in the peer-reviewed medical journal BMC Pregnancy and Childbirth.

The research was covered accurately by The Daily Telegraph. The newspaper focused on the increased risk of preterm birth with a second teenage pregnancy, but did not report the risks of preterm birth associated with first teenage pregnancy. The newspaper is also likely to give the impression that this observation has been made for the first time when, in fact, several previous studies have also noticed this, and it is quite well known in the medical profession.

What kind of research was this?

This research was a cohort study designed to address whether babies born to teenage mothers were more likely to be born early or have a low birthweight. The researchers suggest that some previous studies have found that teenage pregnancy was associated with both an increased risk of preterm birth and low birthweight, although some other studies have found no association.

What did the research involve?

The researchers used a database generated from the Northwestern Perinatal Survey, undertaken at St Mary’s Hospital in Manchester between 2004 and 2006. From this database they found records of all children born to women aged between 14 and 29 years from their first or second pregnancies. The women were classified into three groups according to their age at the time of giving birth: 14-17 years, 18-19 years and 20-29 years of age.

Normal-term pregnancies are generally considered to last 37-40 weeks. In this study the researchers defined preterm delivery as greater than 33 weeks but less than 37 gestation weeks, and very preterm delivery was defined as between 23 and 33 weeks.

They assessed whether the infants had a normal birthweight or were small for gestational age (SGA) using individualised birthweight ratios. These ratios corrected birthweight for gestational age and took into account ethnic origin, gender of the baby, whether the baby was a first or second child and the height and weight of the mother. The babies were considered SGA if their individualised birthweight ratios were in the bottom 5%, and very SGA if they were in the bottom 3%.

They estimated the odds ratios (whether there was an association) between the age of the women and birth outcome of their children using a recognised statistical technique called ‘multiple logistic regression’. In their statistical analyses they adjusted for social deprivation (estimated using the mother’s postcode) and also for the mother’s ethnicity, BMI and whether it was the mother’s first or second child.

Additionally, from 2007 onwards the database contained information on whether mothers smoked at the time of their first antenatal visit. They looked at the data from births in 2007 to assess whether there was an association between smoking, young maternal age, preterm birth and birthweight.

What were the basic results?

There were records of 56,353 births. Of these:

• 3,636 were born to women aged between 14 and 16 years
• 7,506 were born to mothers between 18 and 19 years
• 45,211 babies were born to mothers aged between 20 and 29 years of age

The rates of teenage pregnancy were associated with increasing social deprivation, with more than one third of teenage mothers coming from the most socially deprived areas. There was an even stronger association between social deprivation score and having a second baby before 17 years of age. Teenage mothers were more likely to be underweight and to be of white ethnicity.

In first- or second-time mothers aged between 14 and 17 years the risk of preterm birth was increased relative to the older mothers (20-29 years). The risk was 21% greater during first births and 93% greater during second births (OR 1.21, 95% CI 1.01 to 1.45 and OR 1.93, 95% CI 1.38 to 2.69, respectively).

The risk of having a lower birthweight baby was also greater in mothers under 17 than in older mothers. The mean weight difference was 24g for a first child an 80g for a second child. However, the risk of having a small for gestational age baby was similar in old and young mothers once the researchers applied individualised birthweight ratios to their analyses. (In this study small for gestational age was defined as an individualised birth ratio within the bottom 5% of birthweights. Other studies consider it to be below the lowest 10% or weight below 2,500g at full-term.)

The researchers found that smoking did not seem to have an influence on preterm birth in young mothers, but say that the association between young maternal age and birthweight could be partly related to the confounding effect of smoking.

How did the researchers interpret the results?

The researchers suggest that there is an “association between second teenage delivery and preterm birth and birthweight independent of maternal social deprivation, ethnicity, BMI and smoking”. But they suggest that, unlike in previous studies, there was little evidence for an association between teenage pregnancy and risk of delivering a small for gestational age infant. They recommend that it is appropriate to encourage postnatal health education and the promotion of contraception for teenage mothers to “prevent a second teenage pregnancy with potentially higher risks of adverse outcomes”.

Conclusion

This study has provided evidence that there is an increased risk of teenage mothers having a premature baby, and that the risk further increased for teenage girls having their second child before the age of 17. However, although there are numerous theories behind these associations, this particular study did not address why this may be the case.

Some points to note:

• Although the study adjusted for social deprivation, this adjustment was based on the mother’s postcode, which may not give a true representation of the mother’s living conditions and lifestyle.
• The researchers also noted that there were some missing data on the potential confounding factors. However, the missing data seemed to be spread equally across the maternal age groups and so they suggest that it was unlikely to have affected their estimates.
• The study only had data on maternal smoking from 2007. However, much of the analysis was conducted on data gathered between 2004 and 2006, which means it may not have been fully adjusted to account for the influence of smoking.
• The researchers highlighted that maternal smoking data are often liable to miscalculation as mothers misreport their smoking status, and that many quitters are reported to resume smoking during pregnancy. It is, therefore, possible that the confounding effect of smoking in younger mothers may need further investigation. Smoking during pregnancy has been associated with both prematurity and low birthweight, so is an important confounder in a study such as this.

This study had many strengths, including the use of data from a large population and the fact that the researchers made detailed adjustments for factors influencing birthweight. Further investigation is now needed to assess whether the increased likelihood of preterm babies is due to environmental influences and the teenager’s lifestyle, or to the physical immaturity of the teenage mothers.

Overall, this study highlights the association between preterm births and maternal age, as well as the need for further research into why this is the case. This type of research might aid healthy pregnancies among younger mothers.

Links To The Headlines

Teenage mothers ‘more likely to give birth prematurely’. The Daily Telegraph, July 9 2010

Links To Science

Khashan AS, Baker PN, Kenny LC. Preterm birth and reduced birthweight in first and second teenage pregnancies: a register-based cohort study. BMC Pregnancy and Childbirth 2010, 10:36. July 9 2010

The story is based on research that looked at whether regular chocolate consumption during pregnancy is associated with reduced risks of pre-eclampsia and high blood pressure. It found that a higher chocolate intake in the first or third trimester was associated with a lower risk of pre-eclampsia and in the first three months of pregnancy with a lower risk of high blood pressure.

This study does not provide firm evidence that chocolate consumption can reduce the risk of high blood pressure in pregnancy or pre-eclampsia. However, it does warrant further research into the possible benefits of chocolate. One important limitation is that it relied on women remembering and reporting how much chocolate they ate during pregnancy, which introduces the risk of error.

Chocolate contains caffeine, which should only be consumed in moderate amounts during pregnancy. It is also high in calories and fats. The current advice about chocolate for both pregnant women and everyone else, is to consume it as an occasional treat rather than on a regular basis. Women thought to be at risk of pre-eclampsia during pregnancy should always follow their doctors’ advice.

Where did the story come from?

The study was carried out by researchers from the University of Iowa College of Public Health and Yale University in the US. It was funded by the US National Institutes of Health. The study was published in the peer-reviewed medical journal Annals of Epidemiology.

The Daily Mail’s coverage was fair, although its headline that regular chocolate could halve the risk of premature birth was inaccurate. Premature birth can occur for many reasons, not just as a result of pre-eclampsia. At the same time, pre-eclampsia does not always lead to premature birth, although women who are at high risk may need to be delivered early.

The Mail did mention that the results may have been skewed by women being asked to remember what they had eaten during pregnancy. The newspaper also correctly pointed out that the study failed to distinguish between dark and light chocolate.

What kind of research was this?

This was part of a larger, prospective cohort study about health in pregnancy. This particular study aimed to investigate whether regular chocolate consumption during pregnancy is associated with a reduced risk of pre-eclampsia and hypertension, and whether the risks varied according to the amount of chocolate consumed. The researchers also wanted to find out if the timing or pattern of chocolate consumption during the first and third trimesters had an effect.

The researchers point out that the risk factors for pre-eclampsia are similar to the risk factors for cardiovascular disease. They say that recent studies indicate that regularly eating chocolate (in particular dark chocolate) reduces the risk of cardiovascular disease. It is thought that it does this in several ways, including lowering blood pressure, insulin resistance, blood fats and indicators of inflammation.

Many of these features also apply to pre-eclampsia, providing a ‘strong rationale’ to test for a possible protective effect of chocolate intake. To date, there have been two studies in this area, which reported conflicting results.

What did the research involve?

For their initial interview, the researchers recruited 3,591 women who were less than 16 weeks pregnant. A total of 2,967 women completed the interview, which was conducted in-person by trained personnel, usually at the women’s homes. The women were asked about their medical and reproductive history, height and weight, smoking habits, exercise habits, and alcohol and caffeine intake. They were also asked detailed questions about their chocolate consumption during pregnancy, including both drinks and foods, and asked to recall their average weekly intake of chocolate since becoming pregnant.

The women were interviewed again with the same questions directly after giving birth and asked to recall the last three months of pregnancy. The final analysis was restricted to the 2,508 women who had singleton deliveries and who had hospital delivery records available.

The researchers used the answers from both interviews to calculate consumption patterns separately for the first and third trimesters. The answers were categorised as: less than one serving of chocolate a week, one to three servings a week, and four or more servings a week. They also calculated chocolate consumption for both trimesters combined.

The researchers used blood pressure and urinary protein readings from prenatal and hospital delivery charts to categorise the women as having either high blood pressure, pre-eclampsia or normal blood pressure during pregnancy. Accepted diagnostic definitions were used to do this and the results were validated in a second sample.

The researchers used standard statistical techniques to analyse any potential association between chocolate consumption and the risk of high blood pressure and pre-eclampsia. They adjusted their figures for various potential confounders, including established risk factors for pre-eclampsia such as body mass index (BMI) and maternal age.

What were the basic results?

The researchers found that chocolate intake in the first and third trimesters of pregnancy was more frequent among women with normal blood pressure than among women who developed high blood pressure or pre-eclampsia. Of those who developed pre-eclampsia, 37.5% did not consume chocolate regularly, compared to 19.3% of women who had normal blood pressure and 24.2% of those with high blood pressure.

After adjustment, women who reported regular chocolate consumption (equal to or more than one to three servings a week) had about a 50% reduced risk of pre-eclampsia during the first trimester (OR 0.55,95% confidence interval [CI] 0.32 to 0.95) and the third trimester (OR 0.56, 95% CI 0.32 to 0.97). Only intake of chocolate during the first trimester was associated with a reduced risk of high blood pressure (OR 0.65, 95% CI 0.45 to 0.87).
Since the researchers found no difference in the size of risk between chocolate foods and drinks,  they combined both sources in their analysis.

How did the researchers interpret the results?

The researchers say their findings provide ‘additional evidence’ of the benefits of chocolate and that further studies are needed to confirm and explain the protective effects of chocolate intake on the risk of pre-eclampsia.

They say that the current understanding of pre-eclampsia as a ‘2-stage disease process’ makes it biologically plausible that trimesters one and two would be ‘critical windows’ for possibly lowering the risk.

Conclusion

The findings from this well-conducted study warrant further research, but do not provide firm evidence that chocolate can protect against pre-eclampsia. One problem is the possibility of ‘reverse causality’, with women who developed high blood pressure in pregnancy possibly being less likely to consume chocolate after diagnosis. Although the researchers say that they took account of this possibility by excluding women with high blood pressure before 20 weeks gestation, it is not certain that this applies to the later analyses. They also claim that the protective effects of chocolate were apparent in the first trimester.

A strength of the study is its size, with a large cohort of women being asked detailed questions about chocolate consumption both in early pregnancy and just after delivery. Classification of pre-eclampsia and high blood pressure were also based on accepted definitions and the researchers controlled for risk factors that might influence the outcomes they were studying.

As the authors note, the study has several limitations:

• The women self-reported their chocolate consumption and had to recall their consumption over a relatively long period of time, which raises the chance that errors were introduced.
• It did not differentiate between dark and other types of chocolate.
• No direct measures of any biomarkers were taken (such as theobromine) to validate associations between self-reported chocolate consumption and the risk of pre-eclampsia and high blood pressure.
• It did not assess what else the women were eating during pregnancy, other than caffeine, which could have skewed the results, although the researchers point out that diet is not currently thought of as a risk factor for pre-eclampsia.
• The findings could be biased by underreporting of chocolate intake by overweight women although the researchers say re-ran their analyses to take account of this and got the same results.
• Although many confounders were taken into account, the results could still have been affected by some of these or other unmeasured confounders, such as other foods or drinks associated with chocolate eating that were not recorded.

Women thought to be at risk of pre-eclampsia during pregnancy should always follow their doctors’ advice.

Links To The Headlines

A regular chocolate treat ‘could halve a woman’s risk of giving birth prematurely’. Daily Mail, July 9 2010

Links To Science

Saftlas AF, Triche EW, Beydoun H, et al. Does Chocolate Intake During Pregnancy Reduce the Risks of Preeclampsia and Gestational Hypertension? Annals of Epidemiology 2010; 20: 584-591