OBJECTIVES: To determine the effects of low-to-moderate levels of maternal alcohol consumption in pregnancy on pregnancy and longer-term offspring outcomes.

SEARCH STRATEGY: Medline, Embase, Web of Science and Psych info from inception to 11 July 2016.

SELECTION CRITERIA: Prospective observational studies, negative control and quasi experimental studies of pregnant women estimating effects of light drinking in pregnancy (</=32 g/week) versus abstaining. Pregnancy outcomes such as birth weight and features of fetal alcohol syndrome were examined.

DATA COLLECTION AND ANALYSIS: One reviewer extracted data and another checked extracted data. Random effects meta-analyses were performed where applicable, and a narrative summary of findings was carried out otherwise.

MAIN RESULTS: 24 cohort and two quasi experimental studies were included. With the exception of birth size and gestational age, there was insufficient data to meta-analyse or make robust conclusions. Odds of small for gestational age (SGA) and preterm birth were higher for babies whose mothers consumed up to 32 g/week versus none, but estimates for preterm birth were also compatible with no association: summary OR 1.08, 95% CI (1.02 to 1.14), I2 0%, (seven studies, all estimates were adjusted) OR 1.10, 95% CI (0.95 to 1.28), I2 60%, (nine studies, includes one unadjusted estimates), respectively. The earliest time points of exposure were used in the analysis.

CONCLUSION: Evidence of the effects of drinking </=32 g/week in pregnancy is sparse. As there was some evidence that even light prenatal alcohol consumption is associated with being SGA and preterm delivery, guidance could advise abstention as a precautionary principle but should explain the paucity of evidence.

Published in Pregnant Women

BACKGROUND: Alcohol use during pregnancy is the direct cause of fetal alcohol syndrome (FAS). We aimed to estimate the prevalence of alcohol use during pregnancy and FAS in the general population and, by linking these two indicators, estimate the number of pregnant women that consumed alcohol during pregnancy per one case of FAS.

METHODS: We began by doing two independent comprehensive systematic literature searches using multiple electronic databases for original quantitative studies that reported the prevalence in the general population of the respective country of alcohol use during pregnancy published from Jan 1, 1984, to June 30, 2014, or the prevalence of FAS published from Nov 1, 1973, to June 30, 2015, in a peer-reviewed journal or scholarly report. Each study on the prevalence of alcohol use during pregnancy was critically appraised using a checklist for observational studies, and each study on the prevalence of FAS was critically appraised by use of a method specifically designed for systematic reviews addressing questions of prevalence. Studies on the prevalence of alcohol use during pregnancy and/or FAS were omitted if they used a sample population not generalisable to the general population of the respective country, reported a pooled estimate by combining several studies, or were published in iteration. Studies that excluded abstainers were also omitted for the prevalence of alcohol use during pregnancy. We then did country-specific random-effects meta-analyses to estimate the pooled prevalence of these indicators. For countries with one or no empirical studies, we predicted prevalence of alcohol use during pregnancy using fractional response regression modelling and prevalence of FAS using a quotient of the average number of women who consumed alcohol during pregnancy per one case of FAS. We used Monte Carlo simulations to derive confidence intervals for the country-specific point estimates of the prevalence of FAS. We estimated WHO regional and global averages of the prevalence of alcohol use during pregnancy and FAS, weighted by the number of livebirths per country. The review protocols for the prevalence of alcohol use during pregnancy (CRD42016033835) and FAS (CRD42016033837) are available on PROSPERO.

FINDINGS: Of 23 470 studies identified for the prevalence of alcohol use, 328 studies were retained for systematic review and meta-analysis; the search strategy for the prevalence of FAS yielded 11 110 studies, of which 62 were used in our analysis. The global prevalence of alcohol use during pregnancy was estimated to be 9.8% (95% CI 8.9-11.1) and the estimated prevalence of FAS in the general population was 14.6 per 10 000 people (95% CI 9.4-23.3). We also estimated that one in every 67 women who consumed alcohol during pregnancy would deliver a child with FAS, which translates to about 119 000 children born with FAS in the world every year.

INTERPRETATION: Alcohol use during pregnancy is common in many countries and as such, FAS is a relatively prevalent alcohol-related birth defect. More effective prevention strategies targeting alcohol use during pregnancy and surveillance of FAS are urgently needed.

FUNDING: Centre for Addiction and Mental Health (no external funding was sought).

Published in Pregnant Women

BACKGROUND: It is now well accepted in pediatrics and obstetrics that prenatal alcohol is a teratogenic agent and the primary causative factor underlying fetal alcohol spectrum disorders (FASDs), although for the majority of the 20th century that knowledge was either unknown or ignored. At least 2 factors contributed to the delay in recognizing alcohol's role in teratogenicity: the rejection of earlier evidence pertaining to alcohol and pregnancy following the repeal of Prohibition in the United States, Canada, and several European countries; and misinterpretation of earlier research findings in a eugenic rather than toxicological context. The pervasive belief held well into the 1970s that there was no risk to either mother or fetus from prenatal alcohol posed a major challenge to changing physician and public attitudes on alcohol and pregnancy. This review provides insight on key events that occurred in changing physician and public understanding of the risks posed by prenatal alcohol use in pregnancy.

METHODS: Historical review of events primarily in the U.S. federal government, found in referenced documents.

RESULTS: The transition in physician and public understanding of the risks posed by prenatal alcohol use was aided by the existence of National Institute on Alcohol Abuse and Alcoholism (NIAAA) which was created in 1971. This government agency was able to support research on alcohol and pregnancy immediately following the 1973 published clinical reports calling attention to a proposed fetal alcohol syndrome (FAS). These early research studies provided the foundation for the first government health advisory on alcohol and pregnancy, issued by NIAAA in 1977. Subsequently, the U.S. Food and Drug Administration (FDA) used this new knowledge on FAS in their effort to add alcoholic beverages to the range of products with ingredient and consumer information labeling. The ensuing hearings and actions resulted in a new health advisory under the auspices of the Surgeon General, encouraging avoidance of alcohol consumption in pregnancy. In subsequent years, Congressional attention to the FAS issue resulted in the Alcoholic Beverage Labeling Law.

CONCLUSIONS: The pace at which understanding of the risks of prenatal alcohol moved forward from a total misunderstanding to acceptance was aided by both the efforts of the NIAAA in its support of research, and the FDA in its efforts to improve consumer information. Today, many women in the United States as well as other countries continue to ignore advisories on avoiding alcohol consumption in pregnancy, emphasizing the need for persistence in education on these health risks.

Published in Pregnant Women

OBJECTIVE: The effects of binge-drinking during pregnancy on the fetus and child have been an increasing concern for clinicians and policy-makers. This study reviews the available evidence from human observational studies.

DESIGN: Systematic review of observational studies. Population: Pregnant women or women who are trying to become pregnant.

METHODS: A computerised search strategy was run in Medline, Embase, Cinahl and PsychInfo for the years 1970-2005. Titles and abstracts were read by two researchers for eligibility. Eligible papers were then obtained and read in full by two researchers to decide on inclusion. The papers were assessed for quality using the Newcastle-Ottawa Quality Assessment Scales and data were extracted.

MAIN OUTCOME MEASURES: Adverse outcomes considered in this study included miscarriage; stillbirth; intrauterine growth restriction; prematurity; birth-weight; small for gestational age at birth; and birth defects, including fetal alcohol syndrome and neurodevelopmental effects.

RESULTS: The search resulted in 3630 titles and abstracts, which were narrowed down to 14 relevant papers. There were no consistently significant effects of alcohol on any of the outcomes considered. There was a possible effect on neurodevelopment. Many of the reported studies had methodological weaknesses despite being assessed as having reasonable quality.

CONCLUSIONS: This systematic review found no convincing evidence of adverse effects of prenatal binge-drinking, except possibly on neurodevelopmental outcomes.

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