Pre-pregnancy maternal alcohol consumption not linked to adverse neurodevelopmental outcomes: EJOG

It is widely recognised that alcohol use during pregnancy is a risk factor for miscarriage, stillbirth, intrauterine growth restriction, preterm delivery and low birthweight infants. However, it has also been linked to adverse neurodevelopmental outcomes, and while the most well-known of these is fetal alcohol syndrome disorder, it is also associated with attention deficit hyperactivity disorder, cerebral palsy and poorer educational attainment.

Binge drinking (both during the pre-conception and prenatal period) may be particularly harmful and has been shown to be associated with reduced IQ scores and child behavioural outcomes, although light moderate drinking may also have adverse effects on neurodevelopment. However, results are conflicting, particularly regarding lower levels of alcohol consumption, potentially as a result of inconsistencies in the methodologies used to examine the association.

This study by G.M. Maher et al aimed to examine the association between maternal alcohol consumption (before and during pregnancy) and neurodevelopmental outcomes at age two and five using the Child Behaviour Checklist and Kaufman Brief Intelligence test, while adjusting for several potential confounding factors. Study also aimed to examine the effects of varying degrees of alcohol consumption before and during pregnancy, including binge drinking and timing of binge alcohol exposure. Authors did not find strong evidence of associations between prepregnancy and early pregnancy maternal alcohol consumption and adverse neurodevelopmental outcomes at age two and five years overall.

Retrospective analysis of a prospective longitudinal cohort was carried. Data on preconception and prenatal alcohol consumption were obtained at 15 weeks' gestation and categorised as abstinent, occasional-low (1-7units/week) and moderate-heavy (≥8units/week). Binge drinking was defined as ≥6 units/session. Outcome measures (Child Behaviour Checklist and Kaufman Brief Intelligence Test) were obtained at two and five years.

Data on alcohol consumption was available for 1,507 women. Adjusted linear regression suggested few associations: pre-pregnancy occasional-low alcohol consumption was associated with lower log externalizing Child Behaviour Checklist scores while pre-pregnancy moderate-high levels of alcohol consumption was associated with lower Kaufman Brief Intelligence Test verbal standard scores and composite IQ scores at five-years. In the first trimester, moderate-high levels of alcohol consumption was associated with lower internalizing Child Behaviour Checklist scores at two-years. No significant associations were observed between number of binge episodes pre-pregnancy or binge drinking in the first trimester and Child Behaviour Checklist or Kaufman Brief Intelligence Test.

This study has examined the association between maternal alcohol consumption before and during pregnancy on neurodevelopmental outcomes at age two and five years (using the Child Behaviour Checklist and Kaufman Brief Intelligence Test) as well as examining the effects of binge drinking and timing of binge alcohol exposure. Authors did not find strong evidence of associations between maternal alcohol consumption and adverse neurodevelopmental outcomes overall. Although few associations were observed, the direction of effect was often inconsistent, and it is likely that these associations may have occurred due to chance as a result of multiple testing.

Prepregnancy occasional-low alcohol consumption per week showed a protective association in externalizing Child Behaviour Checklist score, while conversely moderate-high levels of alcohol consumption per week showed a significant reduction in Kaufman Brief Intelligence Test verbal standard score and composite IQ score at age five years. Additionally, in the first trimester, moderate-high levels of alcohol consumption showed a protective effect in internalizing Child Behaviour Checklist score at age two years. With regards to pre-pregnancy binge alcohol consumption, no significant associations were observed between number of binge episodes in the three months prior to conception and Child Behaviour Checklist or Kaufman Brief Intelligence Test scores. Similarly, binge drinking during the first trimester of pregnancy but quit before 15 weeks' gestation was not significantly associated with Child Behaviour Checklist or Kaufman Brief Intelligence Test scores

With regard to binge drinking, this study did not demonstrate any significant association between binge drinking pre-pregnancy or during early pregnancy, on childhood neurodevelopmental outcomes.

"We did not find strong evidence of associations between prepregnancy and early pregnancy maternal alcohol consumption and adverse neurodevelopmental outcomes at age two and five years overall. While few associations were observed, it is likely that many of these occurred as a result of chance given the large number of tests conducted. Although strong associations were not observed in this study, abstinence from alcohol during pregnancy is still considered the safest option considering its effects on other adverse outcomes. As this study was restricted to examining the effects of alcohol consumption before 15 weeks' gestation, further research examining alcohol consumption (including binge drinking) beyond 15 weeks' gestation and neurodevelopmental outcomes is needed to examine the potential effect of alcohol consumption in later pregnancy."

Source: G.M. Maher et al.; European Journal of Obstetrics & Gynecology and Reproductive Biology 274 (2022) 197–203