Systematic Review of effects of low-moderate prenatal alcohol exposure on pregnancy outcome

National Perinatal Epidemiology Unit, University of Oxford, Old Road Campus, Oxford, UK.
BJOG An International Journal of Obstetrics & Gynaecology (Impact Factor: 3.45). 04/2007; 114(3):243-52. DOI: 10.1111/j.1471-0528.2006.01163.x
Source: PubMed


The aim of this study was to review systematically the available evidence on studies in humans on the effects of low-moderate levels of prenatal alcohol consumption (up to 10.4 UK units or 83 g/week) compared with consumption of no alcohol on pregnancy outcome.
Systematic review.
Pregnant women or women who are trying to become pregnant.
The search strategy included Medline, Embase, Cinahl and PsychInfo for the years 1970-2005. Titles and abstracts were read by two researchers and inclusion/exclusion being decided according to prespecified criteria. All the included articles were then obtained and read in full by the two researchers to decide on inclusion. The articles were assessed for quality using the Newcastle-Ottawa Quality Assessment Scales.
Outcomes considered were miscarriage, stillbirth, intrauterine growth restriction, prematurity, birthweight, small for gestational age at birth and birth defects including fetal alcohol syndrome.
The search resulted in 3630 titles and abstracts, which were narrowed down to 46 relevant articles. At low-moderate levels of consumption, there were no consistently significant effects of alcohol on any of the outcomes considered. Many of the reported studies had methodological weaknesses.
This systematic review found no convincing evidence of adverse effects of prenatal alcohol exposure at low-moderate levels of exposure. However, weaknesses in the evidence preclude the conclusion that drinking at these levels during pregnancy is safe.

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    • "These inconsistent findings of risk at relatively high consumption levels and no risk and/or reduced risk at moderate and low levels may be due to the heterogeneity across studies, large divergence in defining and measuring alcohol consumption, and that some findings are not adjusted for important lifestyle and related socioeconomic factors [4,19e21]. Another source of confounding could be undetected differences in health-related behavior due to previous reproductive experience [21] or due to the presence of publication bias [3]. Most pregnant women in Norway either abstain from alcohol or drink occasionally. "
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    ABSTRACT: Purpose: Our aim was to explore the association between alcohol consumption, before and during pregnancy, and the risk of preterm birth among 46,252 primiparous mothers. Methods: We obtained information on alcohol consumption from questionnaire responses at pregnancy week 15 from the prospective, observational Norwegian Mother and Child Cohort Study. Data on preterm birth, categorized as delivery before gestation week 37, were retrieved from the Medical Birth Registry of Norway. Results: Among the participants, 91% consumed alcohol before pregnancy and fewer than 20% reported consuming alcohol during pregnancy. The adjusted odds ratio (aOR) for preterm birth associated with prepregnancy alcohol consumption was 0.81 (95% confidence interval [CI], 0.70-0.95). We did not find a risk reduction for overall drinking during pregnancy, aOR = 1.03 (95% CI, 0.90-1.19). However, dose-response analyses showed tendencies toward adverse effects when drinking 1-3 times per month during the first 15 weeks of pregnancy, aOR = 1.51 (95% CI, 1.14-2.00). Conclusions: We did not find any effects of alcohol consumption during pregnancy, whereas pre-pregnancy drinking was associated with reduced risk of preterm birth. Residual confounding may have influenced the risk estimates, especially before pregnancy, as nondrinkers have lower socioeconomic status and well-being than drinkers.
    Full-text · Article · Sep 2015 · Annals of epidemiology
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    • "In addition to a need for more studies directly measuring attention in animal models of FASD and ADHD, another contentious point relates to the route of administration and the minimum dose of ethanol needed to induce structural or behavioral consequences. Perhaps due to the difficulty in adequately controlling for factors such as dose, genetics and bias associated with the often-used method of self-report (Huizink, 2009), the literature is inconsistent with respect to the effects of small doses of ethanol (equivalent to one to two drinks a week) on the offspring (Abate et al., 2008; Henderson et al., 2007; Huizink, 2009; Kelly et al., 2008; Polygenis et al., 1998; Sood et al., 2001). In comparison with injection, putting alcohol in drinking water or intragastric gavage, the use of liquid diets (nutritional preparations containing differing amounts of ethanol) allows for more stable levels of blood alcohol concentration – BAC (Driscoll et al., 1990; Uzbay and Bizarro, 2010). "
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    ABSTRACT: Rationale Decline of attentional performance as a function of time engaged on a task and hyperactivity are features shared by children and adults with fetal alcohol syndrome or attentional deficit and hyperactivity disorders. Objective To investigate the effects of prenatal exposure to two doses of ethanol on developmental milestones, locomotor activity and attention. Methods Wistar rats born from dams exposed to one of four maternal treatments during pregnancy were used: A35 - liquid diet with 35% ethanol-derived calories; A10 - liquid diet with 10% ethanol-derived calories; control - ethanol-free liquid diet; chow - laboratory chow and water. Results A35 performed worse in grip strength than control and chow (postnatal day - 14, p < 0.05) but not in negative geotaxis (postnatal days 7-10); A35 also showed more locomotor activity than control and A10 (p < 0.05). Regarding attention, acquisition of the five choice reaction time task was similar between groups, but, the percentage of omission errors from A35 group was greater than other groups at baseline parameters, at shorter (2 s) and longer (7 s) inter-trial intervals and at a shorter stimulus duration (0.5 s) (p < 0.05). The percentage of omissions was larger in A35 as the blocks progressed in sessions with either longer or shorter inter-trial intervals (group × block p < 0.05). Animals from A10 group did not show any impairment in the tasks performed. Conclusions our study demonstrates that as well as developmental impairments, prenatal ethanol can produce deficits associated with an increase in attentional demand in rodents, analogous to those observed in fetal alcohol syndrome and attentional deficit and hyperactivity disorders.
    Full-text · Article · Nov 2014 · International Journal of Developmental Neuroscience
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    • "Factors reported in the literature to be both predictors of PAE and adverse child outcomes associated with PAE, but not on the causal pathway are: maternal age 30 years and older; [26] pregnancy wantedness; [27] increasing parity [28] and obstetric history [3]. Further potential confounders collected as repeated measures across all questionnaires include maternal psychological wellbeing, [26–30] smoking, [28, 31, 32] illicit substances, [27, 33] medication and supplement use, particularly folate [14, 34]. "
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    ABSTRACT: Background Despite extensive research, a direct correlation between low to moderate prenatal alcohol exposure (PAE) and Fetal Alcohol Spectrum Disorders has been elusive. Conflicting results are attributed to a lack of accurate and detailed data on PAE and incomplete information on contributing factors. The public health effectiveness of policies recommending complete abstinence from alcohol during pregnancy is challenged by the high frequency of unplanned pregnancies, where many women consumed some alcohol prior to pregnancy recognition. There is a need for research evidence emphasizing timing and dosage of PAE and its effects on child development. Methods/Design Asking QUestions about Alcohol (AQUA) is a longitudinal cohort aiming to clarify the complex effects of low to moderate PAE using specifically developed and tested questions incorporating dose, pattern and timing of exposure. From 2011, 2146 pregnant women completed a questionnaire at 8-18 weeks of pregnancy. Further prenatal data collection took place via a questionnaire at 26-28 weeks and 35 weeks gestation. Extensive information was obtained on a large number of risk factors to assist in understanding the heterogeneous nature of PAE effects. 1571 women (73%) completed all three pregnancy questionnaires. A biobank of DNA from maternal and infant buccal cells, placental biopsies and cord blood mononuclear cells will be used to examine epigenetic state at birth as well as genetic factors in the mother and child. Participants will be followed up at 12 and 24 months after birth to assess child health and measure infant behavioural and sensory difficulties, as well as family environment and parenting styles. A subgroup of the cohort will have 3D facial photography of their child at 12 months and a comprehensive developmental assessment (Bayley Scales of Infant & Toddler Development, Bayley-III) at two years of age. Discussion Using detailed, prospective methods of data collection, the AQUA study will comprehensively examine the effects of low to moderate alcohol consumption throughout pregnancy on child health and development, including the role of key mediators and confounders. These data will ultimately contribute to policy review and development, health professional education and information about alcohol consumption for pregnant women in the future.
    Full-text · Article · Sep 2014 · BMC Pregnancy and Childbirth
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