Risk of postpartum episodes in women with bipolar disorder after lamotrigine or lithium use during pregnancy: A population-based cohort study.

BACKGROUND: Women with bipolar disorder are at high risk for relapse/recurrence postpartum. Among all mood stabilizers, lithium has the largest evidence base for efficacy in the peripartum period, but lamotrigine is increasingly prescribed for bipolar spectrum disorders during pregnancy. The aim of this study was to investigate whether lamotrigine use during pregnancy is as effective as lithium in the prevention of severe episodes postpartum.

METHODS: Danish national registries were used to identify pregnancies of women with a diagnosis of bipolar spectrum disorders at the time of conception who used lamotrigine or lithium during pregnancy. We compared the risk of inpatient psychiatric admission within three months postpartum between women who used lamotrigine (N=55) versus lithium (N=59) during pregnancy. A logistic regression model was used to calculate crude and adjusted odds ratios.

RESULTS: We did not find a significant difference in the risk of postpartum psychiatric admission between women who used lamotrigine versus lithium during pregnancy (7.3% versus 15.3% respectively, adjusted OR 0.83; 95% CI 0.22-3.14). We adjusted for year of delivery, parity, previous admissions and antidepressant/benzodiazepine use during pregnancy. Other variables did not differ substantially between groups.

LIMITATIONS: We used an observational design and therefore patients were not randomized to lamotrigine or lithium. The study has a small sample size.

CONCLUSIONS: Lamotrigine was not inferior to lithium in the prevention of severe postpartum episodes. Our findings suggest lamotrigine could be a reasonable alternative treatment option for bipolar disorder during pregnancy in patients with vulnerability for depression and may prevent severe episodes postpartum.