Women who drink heavily during pregnancy have increased stillbirth risk
- 1College of Nursing, Wayne State University, Detroit, MI, USA
- 2 Department of Obstetrics and Gynecology, Wayne State University, Detroit, Michigan, USA
- Correspondence to
: Robert J Sokol
Department of Obstetrics and Gynecology, Wayne State University, 275 E. Hancock, Detroit, MI 48201, USA;
Implications for practice and research
Identification of fetal risk alcohol exposure has proven difficult. It is important to understand differential risk factors.
In practice, it is worthwhile to put systems in place to screen for risky drinking both before and during pregnancy as a prelude to intervention to reduce embryonic/fetal alcohol exposure.
Future research should focus on confirming the alcohol-related risks for stillbirth and identifying interventions that will decrease prenatal alcohol exposure and are effective across diverse populations (ie, work across multiple practice settings).
The context of this study is particularly important because this article relates to long-held concerns about the effect of maternal alcohol use during pregnancy and significant health disparities between Aboriginal and non-aboriginal women and children in Australia. Stillbirth has been identified as an adverse outcome related to prenatal alcohol exposure, but this relationship has not been evaluated in these Australian populations. Many studies in other geographical areas have shown a substantial increase in the range of alcohol-related adverse pregnancy outcomes in minority populations, including in African-Americans, Native Americans and ‘coloured’ South Africans.1 Why these minority groups seem more vulnerable to the adverse effects of in utero alcohol exposure remains controversial.
The relationship between prenatal alcohol exposure and stillbirth frequency was examined using a cohort of mothers in Western Australia (WA) with an International Classification of Diseases alcohol-related diagnosis of over 24 years. This exposed group was stratified by indigenous status; aboriginal (n=9910; 32%) and non-aboriginal (n=13 919; 26%). The presence of an alcohol-related diagnosis among women aged 10 years or older was identified using multiple databases. Diagnosis timing was stratified as >1 year before pregnancy; within the year prior to pregnancy; during pregnancy; within 1 year postpregnancy and >1 year postpregnancy. Presence of an alcohol-related diagnosis was used as a proxy for heavy alcohol consumption during pregnancy and embryonic/fetal exposure. Separate logistic regressions were performed for overall diagnosis status and, for each diagnosis, time period to obtain the odds ratio for stillbirth stratified by aboriginal status. Each analysis controlled for maternal age, year of infant birth, marital status, parity, illicit drug use and mental health status.
After covariate control, an alcohol-related diagnosis was linked to an increased risk of stillbirth in both non-aboriginal and aboriginal women; adjusted OR=1.33 (95% CI 1.08 to 1.64) and 1.36 (95% CI 1.05 to 1.76) for aboriginal and non-aboriginal women, respectively. Although there was an overall effect, the percentage of women who had a stillborn child was highest among aboriginal women with an alcohol-related diagnosis identified within the first year postpregnancy (adjusted OR=2.88; 95% CI 1.75 to 4.75).
A relationship between prenatal alcohol exposure and increased pregnancy loss (spontaneous early and late abortion and stillbirth) has been detected in multiple studies almost since the recognition of alcohol as a pregnancy risk. In this study, the detected effect size on stillbirth was small (an increase in a rare event of about 1/3); nonetheless, the impact of alcohol exposure on stillbirth is 100% avoidable. This suggests that detecting alcohol problem or heavy drinking by women before and during pregnancy and interventions to decrease or avoid fetal exposure are worthwhile. Although overall alcohol-related diagnosis was linked to elevated rates of stillbirth in both cohorts, higher rates were seen when the diagnosis was made within the first year postpregnancy. This might suggest that women who received a diagnosis during pregnancy also received intervention, thus reducing or eliminating their alcohol intake for the remainder of the pregnancy. More description of diagnosis timing might have been helpful, but the findings regarding the timing of diagnosis are far from robust and should not be overinterpreted. Any alcohol diagnosis at any time in this study is a surrogate for presumed heavy drinking during pregnancy. Nonetheless, this should not minimise the reader's recognition of the important relationship between alcohol exposure and stillbirth.
Fetal alcohol-related risk recognition is difficult to achieve, often because of maternal under-reporting. In this study, the need to use a surrogate measure makes it impossible to evaluate critical periods/thresholds. Thus, the relationship identified in this research may actually underestimate the true effect size.
The ‘bottom line’ is that to avoid adverse consequences, including stillbirth, abstinence during pregnancy is advised. Based on this and other emerging work, screening, brief intervention and referral for treatment (SBIRT) might be effective in the pregnancy setting.2 Further studies should focus on prevention.