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

Abstract

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 = 5839; Aboriginal n = 2583) 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 = 8005). 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.

Pregnancy outcomes of mothers with an alcohol‐related diagnosis: a population‐based cohort study for the period 1983–2007

“…21 The population eligible to be included in this study comprised all women who have had a birth recorded on the Midwives Notification System (MNS) in WA between 1983 and 2007. The MNS is a statutory notification system that has routinely collected all WA births (at >20 weeks of gestation, with birthweights of >400 g, including stillbirths) since 1980.…”

“…23 The exposure status of mothers was identified through linkage with data from the WA Data Linkage System, including the Hospital Morbidity Data System, Mental Health Outpatient data set, and Perth-based Drug and Alcohol treatment services data set. 21 Probabilistic matching was used by the WA Data Branch to link data from administrative data sets. 24 …”

“…21 The diagnoses included acute alcohol intoxication, alcohol dependence, alcohol-related psychiatric conditions, alcohol-related disease, and fetal alcohol harm in the baby (Table S1). The presence of an alcoholrelated diagnosis was used as a proxy for heavy maternal alcohol consumption and as a proxy for heavy prenatal alcohol exposure when the diagnosis was recorded during pregnancy.…”

“…Contributing factors may be that pregnant Aboriginal women are more open about their drinking or that they may be more likely to present to hospital intoxicated than non-Aboriginal women. 21 …”

“…20 This New South Wales study did not examine the outcomes separately for non-Aboriginal and Aboriginal mothers, however, and only examined the fetal outcomes of mothers with an alcohol diagnosis recorded during pregnancy, which has been shown to under-represent exposure. 21,22 No Australian studies have calculated the population-attributable fractions for poor neonatal outcomes in infants of mothers with an alcohol-related diagnosis. The calculation of the attributable fractions would provide important information about the public health impact of maternal alcohol-use disorder on the fetus.…”