Alcohol-use disorders during and within one year of pregnancy: a population-based cohort study 1985-2006

OBJECTIVES

To examine alcohol-use disorders in pregnant women and the extent of under-reporting.

DESIGN

Population-based cohort study.

SETTING

Western Australia.

POPULATION

Women with a birth recorded on the Western Australian Midwives Notification System (1985-2006).

METHODS

Mothers with an International Classification of Diseases 9/10 alcohol-related diagnosis, indicating heavy alcohol consumption, recorded on population-based health datasets (non-Aboriginal n=5,839; Aboriginal n=2,583) were identified through the Western Australian data-linkage system. This 'exposed' cohort was frequency matched (on maternal age, year of birth of offspring, Aboriginal status) with comparison mothers without an alcohol-related diagnosis (non-Aboriginal n=33,979; Aboriginal n=8,005).

MAIN OUTCOME MEASURES

Trends in maternal alcohol diagnoses in relation to pregnancy for non-Aboriginal and Aboriginal women. The proportion of children diagnosed with fetal alcohol syndrome (FAS) who had a mother with an alcohol diagnosis recorded during pregnancy.

RESULTS

The proportion of Aboriginal mothers in Western Australia with an alcohol diagnosis (23.1%) is ten times greater than for non-Aboriginal mothers (2.3%). There has been a six-fold increase in the percentage of non-Aboriginal births with a maternal alcohol diagnosis recorded during pregnancy and a 100-fold increase for Aboriginal births. Around 70% of the mothers of children diagnosed with FAS did not have an alcohol diagnosis recorded during pregnancy and 18% of the mothers had no record of an alcohol diagnosis.

CONCLUSIONS

Maternal alcohol exposure during pregnancy is significantly under-ascertained. Given the severe risks to the fetus from heavy prenatal alcohol exposure, assessment and recording of alcohol use should be routinely undertaken in maternity and other health settings.

Heavy prenatal alcohol exposure and increased risk of stillbirth

OBJECTIVE

To investigate the association between heavy prenatal alcohol exposure and stillbirth.

DESIGN

Data linkage cohort study.

SETTING

Western Australia (WA).

POPULATION

The exposed cohort included mothers with an alcohol-related diagnosis (International Classification of Diseases, ninth/tenth revisions) recorded in health data sets and all their offspring born in WA (1983-2007). Mothers without an alcohol-related diagnosis and their offspring comprised the comparison cohort.

METHODS

Exposed and comparison mothers were identified through the WA Data Linkage System. Odds ratios for stillbirth at 20+ weeks of gestation were estimated by logistic regression, stratified by Aboriginal status.

MAIN OUTCOME MEASURES

The proportion of stillbirths at 20+ weeks of gestation is presented per 1000 births, as well as adjusted odds ratios (aOR) and 95% confidence intervals (95% CI), and population-attributable fractions.

RESULTS

Increased odds of stillbirth were observed for mothers with an alcohol-related diagnosis at any stage of their life for both non-Aboriginal (aOR 1.36; 95% CI 1.05-1.76) and Aboriginal (aOR 1.33; 95% CI 1.08-1.64) births. When an alcohol diagnosis was recorded during pregnancy, increased odds were observed for non-Aboriginal births (aOR 2.24; 95% CI 1.09-4.60), with the highest odds of Aboriginal stillbirth occurring when an alcohol diagnosis was recorded within 1 year postpregnancy (aOR 2.88; 95% CI 1.75-4.73). The population-attributable fractions indicate that 0.8% of non-Aboriginal and 7.9% of Aboriginal stillbirths are the result of heavy alcohol consumption.

CONCLUSIONS

Prevention of heavy maternal alcohol use has the potential to reduce stillbirths. The lack of an association between exposure during pregnancy and Aboriginal stillbirth in this study needs further investigation.