Pregnancy outcomes of mothers with an alcohol-related diagnosis: A population-based cohort study for the period 1983-2007

Objective

To examine fetal outcomes of mothers with an alcohol-related diagnosis.

Design

Population-based cohort.

Setting

Western Australia (WA).

Population

Births on the WA Midwives Notification System (1983–2007).

Methods

Infants of mothers with an alcohol-related diagnosis [International Classification of Disease (ICD), 9th/10th revisions] recorded on WA health data sets (non-Aboriginal n = 13 807; Aboriginal n = 9766) were identified through the WA data linkage system. A comparison cohort of infants born to mothers without an alcohol diagnosis was frequency matched on maternal age, year of birth of the offspring, and Aboriginal status (non-Aboriginal n = 40 148; Aboriginal n = 20 643).

Main outcome measures

Poisson regression-generated adjusted relative risk (aRR) and 95% confidence intervals (95% CIs) for small for gestational age (SGA), preterm birth, and low-Apgar score, calculated separately for non-Aboriginal and Aboriginal infants of mothers with an alcohol diagnosis recorded during pregnancy and any alcohol diagnosis. Population-attributable fractions were calculated.

Results

The aRR for non-Aboriginal infants when a maternal alcohol diagnosis was recorded during pregnancy ranged from 1.79 (95% CI 1.42–2.16) for SGA to 2.57 (95% CI 1.69–4.27) for preterm birth <32 weeks of gestation, and for Aboriginal infants ranged from 2.69 (95% CI 2.28–3.16) to 1.99 (95% CI 1.40–2.84), respectively. The highest population-atributable fractions were for any alcohol diagnosis and for Aboriginal infants. For Aboriginal births, approximately 9% (95% CI 4.74–12.97) and 10.1% (95% CI 5.50–14.49) of moderate and very preterm births, respectively, and 24.4% (95% CI 13.5–21.2%) of SGAs were attributable to having a mother with any alcohol-related diagnosis.

Conclusions

Mothers with an alcohol diagnosis are at increased risk of poor pregnancy outcomes. The public health impact of maternal alcohol-use disorders on fetal outcomes is significant.