Protective Effects of Pregnancy on Risk of Alcohol Use Disorder

Objective: The authors sought to clarify the etiology of the association between pregnancy and reduced risk of alcohol use disorder.

Methods: The authors used data from longitudinal population-wide Swedish medical, pharmacy, and criminal registries to evaluate whether rates of alcohol use disorder are lower during pregnancy. They compared pregnant women born between 1975 and 1992 (N=322,029) with matched population controls, with female relatives discordant for pregnancy, and with pre- and postpregnancy periods within individuals. They further compared rates of alcohol use disorder between pregnant women and their partners.

Results: Pregnancy was inversely associated with alcohol use disorder across all analyses (odds ratios, 0.17-0.32). In co-relative analyses, the strength of the association increased among more closely related individuals. Within individuals, rates of alcohol use disorder were substantially decreased during pregnancy relative to the prepregnancy period (odds ratios, 0.25-0.26), and they remained reduced during postpartum periods (odds ratios, 0.23-0.31). Results were similar for second pregnancies (odds ratio, 0.23). The partners of pregnant women also exhibited reductions in alcohol use disorder (odds ratio, 0.45). Among women who became pregnant at earlier ages and those with a history of criminal behavior, the negative association between pregnancy and alcohol use disorder was especially pronounced, but no moderation was observed for a personal or maternal parental history of alcohol use disorder.

Conclusions: The findings suggest that pregnancy plays a critical, and likely causal, motivational role in reducing alcohol use disorder risk among women and, to a lesser extent, their partners. These results extend our understanding of the relationship between pregnancy and alcohol use, demonstrating that even a severe condition such as alcohol use disorder is subject to the protective effects of pregnancy.