Critique 107: Little effect on child’s mental functioning associated with mother’s light, occasional drinking in early pregnancy – 25 March 2013

Sayal K, Draper ES, Fraser R, Barrow M, Davey Smith G, Gray R.  Light drinking in pregnancy and mid-childhood mental health and learning outcomes.  Arch Dis Child 2013;98:107–111. doi:10.1136/archdischild-2012-302436.

Authors’ Abstract

Objective To investigate whether light drinking in pregnancy is associated with adverse child mental health and academic outcomes.

Design  Using data from the prospective, population-based Avon Longitudinal Study of Parents and Children (ALSPAC), we investigated the associations between light drinking in pregnancy (<1 glass per week in the first trimester) and child mental health (using both parent and teacher rated Strengths and Difficulties Questionnaires (SDQs)) and academic outcomes based on Key Stage 2 examination results at age 11 years.

Participants  11-year-old children from ALSPAC with parent (n=6,587) and teacher (n=6,393) completed SDQs and data from Key Stage 2 examination results (n=10,558).

Results  39% of women had consumed <1 glass per week and 16% ≥1 glass per week of alcohol during the first trimester (45% abstaining).  After adjustment, relative to abstainers, there was no effect of light drinking on teacher-rated SDQ scores or examination results.  In girls, although there was a suggestion of worse outcomes (adjusted regression coefficient=0.38; 95% CI 0.01 to 0.74) on the parent-rated total SDQ score in those exposed to light drinking compared to abstainers, no dose–response relationship was evident.

Conclusions  Although the pattern of findings involving parent ratings for girls exposed to light drinking is consistent with earlier findings from this cohort, the overall lack of any adverse effects of light drinking is similar to findings from other recent cohort studies.  Light drinking in pregnancy does not appear to be associated with clinically important adverse effects for mental health and academic outcomes at the age of 11 years.

Forum Comments

While any alcohol consumption during pregnancy is not encouraged, and heavy drinking is associated with an increase in risk of a number of adverse health outcomes in the fetus, there is controversy as to whether the occasional drink by the mother during pregnancy has any detectable effect on the child.  The present study is based on cognitive and behavioral assessments in a large cohort of children at age 11 in relation to the mother’s reporting of alcohol intake during the first trimester. 

Specific comments on study:  Information on the frequency of the mother’s alcohol consumption during the first trimester was obtained by questionnaire completed at 18 weeks gestation.  Categories of intake were “never,” “less than 1 glass per week,” “at least 1 glass per week,” “1–2 glasses a day,” “3–9 glasses a day,” or “more than 10 glasses a day.”  Examples were given to specify that one glass was equivalent to one UK unit (8 g) of alcohol.  For the analyses, the groups consuming ≥1 glasses per week were combined and compared with groups not consuming alcohol and those reporting < 1 drink/week.  Forum reviewer Waterhouse commented: ¨It is unfortunate that these investigators had data on subjects with daily consumption but chose to combine it into a group consuming alcohol at least weekly.  By combining these groups their report only says that consuming more than one drink per week is OK, but does not comment specifically on more frequent consumption.”

Child mental health outcomes were assessed using both the parent- and teacher-completed Strengths and Difficulties Questionnaire (SDQ) at the age of 11 years.  This instrument includes four sub-scales relating to emotional problems, conduct problems, hyperactivity / inattention, and peer relationships; higher scores indicate greater levels of severity.  The analyses focus on the two behavioral problem sub-scales (conduct problems and hyperactivity/inattention) as well as the total problems score.  Academic outcomes were assessed using standardized, age-adjusted total scores from results on the Key Stage 2 (KS2) examinations taken during the final year at primary (elementary) school, at ages 10–11 years.  The authors state that these scores provide an objective real world measure of academic performance.

Forum reviewers considered this to be a well-done analysis, with adjustments for key maternal variables (age, maternal education, parity, use of cannabis and other illicit drugs in the first trimester, housing, marriage status, maternal smoking, maternal mental health) and child factors, that included gestational age, birth weight, and gender.  There were adequate numbers of subjects for comparison who consumed no alcohol during the first trimester (n=5,547) and those who reported some alcohol intake but < 1 drink/week (n=4, 776). 

 A total of 1,973 women reported that they consumed ≥ 1 drink/week.  Unfortunately, despite having almost 2,000 subjects in this group, there are no analyses separating the effects among these women according to sub-groups of intake.  States reviewer Skovenborg: “The reason for the arbitrary separation of alcohol consumption (<1 drink per week versus ≥1 drink per week) among a group of pregnant women with a very heterogenous alcohol intake is not explained by the authors.  Current guidance about alcohol consumption in pregnancy from the Department of Health in England (2009) allows for pregnant women to drink up to 1–2 units of alcohol once or twice a week.  Thus, a better choice of response categories in the present study would have included one for this amount of alcohol.”  A total of 238 women in this study reported drinking daily, but separate results are not given even for these subjects.   

The authors state that the key results of the paper are that “Light drinking in pregnancy does not appear to be associated with adverse mental health or academic consequences at the age of 11 years.”  This same research group had previously reported adverse effects up to age 8 among girls in this cohort, but state that the current analyses do not support adverse academic or behavioral effects at age 11 in either girls or boys.  Reviewer Finkel stated: “I remember well the series of previous reports from this group.  Some were alarming, raising doubts about what had seemed a sensible position that small, spaced quantities of an alcoholic beverage were unlikely to harm the fetus.  This new study seems reliably done, and the conclusions appear sensible.”

Should any alcohol intake during pregnancy be discouraged?  Forum Co-Director Conibear provided some interesting insight: “The most important thing from the public’s point of view is that The Food Doctor and the UK charity ‘New Life,’ which helps research related to sick and disabled babies, found that 25% of babies in the UK are unplanned, and 17% of mothers didn’t know they were pregnant until eight weeks or more.  Therefore balanced advice concerning the effect of alcohol use in pregnancy is crucial to prevent unnecessary concern amongst this group of mothers to be.  Although the best advice is to avoid alcohol if you are pregnant, the present research can reassure mothers who drank occasionally without realising that they were pregnant that they had not done long-term harm to their baby.”

Forum member Lanzmann added: “The French traditional attitude toward wine consumption during meals can also play a role, as food slows down the increase of blood alcohol level after drinking; this will benefit both the mother and the fetus.”  She adds: “The French National Nutrition & Health Program’s 2^nd specific objective is an adequate folate status for every woman during the age of procreation, because folic acid deficiency is very common.  In such a case, if a diagnosis of an unplanned pregnancy is not made until after 8 weeks, the mother will still have adequate folate on board during the critical time when the embryo’s neural tube closure is occurring (as this is by the 29^th day of gestation).”  

Reviewer Skovenborg comments: “The question of alcohol consumption during pregnancy is a toxic subject that is not ruled by evidence-based discussion: evidence is outdone by emotions, case reports, and pseudo-scientific arguments like ‘no safe threshold for drinking during pregnancy has been documented.’  Irrespective of the amount of evidence, the advice of total abstinence will always be the largest trump.” 

Forum reviewer Van Velden states: “In my country (South Africa), with probably the highest reported incidence in the world of fetal alcohol syndrome, alcohol consumption during pregnancy will always be ‘criminalized!’”  Reviewer Orgogozo adds: “While wine consumption throughout pregnancy was the usual practice in France in the past, now any drinking during pregnancy is looked upon with much suspicion – mainly on an  emotional basis.  But, facts are facts, and the present paper is well documented and argued, and I agree with the comments of other reviewers.  Deciding on zero intake during pregnancy is based primarily on beliefs – it has become a moral attitude.  This should not take precedence over scientific and factual evidence.”

Reviewer Stockley adds another point: “I think that another important message that should get out is that if a woman decides to consume a small amount of alcohol during pregnancy, she should never binge drink or get drunk.  This we know with relative certainty can have adverse effects on the developing fetus, especially in the first trimester, but interestingly, also in the third trimester.” 

Forum Summary

A new report from the prospective, population-based Avon Longitudinal Study of Parents and Children (ALSPAC) in the UK is based on investigation of the association between light drinking in pregnancy (<1 glass per week in the first trimester) and child mental health.  Mental health was assessed in more than 6,000 children using both parent- and teacher-rated Strengths and Difficulties Questionnaires (SDQs) at age 11 years.  Academic outcomes based on Key Stage 2 examination results were measured in more than 10,000 children.  

Approximately 40% of women consumed some alcohol but less than 1 glass/week, while 16% reported consuming ≥1 glass per week during the first trimester.  The authors report that after adjustment, relative to abstainers, there was no effect of light drinking on teacher-rated scores or examination results.  In girls, although there was a suggestion of worse outcomes on the parent-rated total score in those exposed to light drinking compared to abstainers, no dose–response relationship was evident.  The authors conclude: “Light drinking in pregnancy does not appear to be associated with clinically important adverse effects for mental health and academic outcomes at the age of 11 years.”

Forum reviewers considered this to be a well-done study, with a balanced assessment of results by the authors.  Reviewers were surprised at the somewhat arbitrary separation of alcohol consumption: <1 drink per week versus ≥1 drink per week.  Current guidance about alcohol consumption in pregnancy from the Department of Health in England (2009) allows for pregnant women to drink up to 1–2 units of alcohol once or twice a week, and it would have been preferable to have data presented for drinkers at this level. 

Forum Co-Director Conibear considered that “The most important aspect of this study relates to the fact that 25% of babies in the UK are unplanned, and 17% of mothers do not know they are pregnant until eight weeks or more.  Therefore balanced advice concerning the effect of alcohol use in early pregnancy is crucial to prevent unnecessary concern amongst this group of mothers to be.  Although the best advice is to avoid alcohol if you are pregnant, the present research can reassure mothers who drank occasionally without realising that they were pregnant that they have not done long-term harm to their baby.”

Forum reviewer Stockley added: “I think that another important message is that if a woman decides to consume a small amount of alcohol during pregnancy, she should never binge drink or get drunk.  This we know can have adverse effects on the developing fetus, especially in the first trimester, but interestingly, also in the third trimester of pregnancy.” 

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Comments on this critique were provided by the following members of the International Scientific Forum on Alcohol Research:

Giovanni de Gaetano, MD, PhD, Research Laboratories, Catholic University, Campobasso, Italy

R. Curtis Ellison, MD, Section of Preventive Medicine & Epidemiology, Boston University School of Medicine, Boston, MA, USA

Harvey Finkel, MD, Hematology/Oncology, Boston University Medical Center, Boston, MA, USA

Dominique Lanzmann-Petithory,MD, PhD, Nutrition/Cardiology, Praticien Hospitalier Hôpital Emile Roux, Paris, France

Jean-Marc Orgogozo, MD, Professor of Neurology and Head of the Neurology Divisions, the University Hospital of Bordeaux, Pessac, France

Erik Skovenborg, MD, Scandinavian Medical Alcohol Board, Practitioner, Aarhus, Denmark

Creina Stockley, PhD, MBA, Clinical Pharmacology, Health and Regulatory Information Manager, Australian Wine Research Institute, Glen Osmond, South Australia, Australia

Arne Svilaas, MD, PhD, general practice and lipidology, Oslo University Hospital, Oslo, Norway

David Van Velden, MD, Dept. of Pathology, Stellenbosch University, Stellenbosch, South Africa

Andrew L. Waterhouse, PhD, Marvin Sands Professor, Department of Viticulture and Enology, University of California, Davis; Davis, CA, USA