Obstetric outcomes regarding the use of lithium in pregnant women with bipolar disorders: a prospective cohort study

Lithium is the mood stabilizer of choice for the prevention of bipolar relapse over the perinatal period. A critical issue is its safety of the mother and the developing fetus. This study aims to compare obstetric outcomes in women with bipolar disorders (BD) regarding treatment with lithium during pregnancy. We enrolled a cohort of pregnant women with BD that received care at the Perinatal Mental Health Unit of a tertiary hospital between January 2005 and March 2017. The exposed group received lithium during pregnancy, whereas the unexposed group did not. The main outcomes were obstetric complications during pregnancy, during labor and delivery, neonatal complications, and congenital malformations. Demographic and clinical data were described using measures of frequency, central tendency, and dispersion. Between-group differences were calculated with chi-square, Fisher's test, t-tests, or Mann-Whitney U test. Our cohort included 100 pregnant women with BD: 53 (53%) used lithium during pregnancy, and 47 (47%) did not. There were no significant differences in obstetric complications, neonatal complications, or congenital anomalies. Nonetheless, newborns of lithium-treated women had lower Apgar scores at 1 min (mean 8.2 +/- 1.6 vs. 8.9 +/- 0.6, p = 0.026) and 5 min (9.6 +/- 0.8 vs. 9.9 +/- 0.5, p = 0.015). Our findings do not identify worse obstetric outcomes in women with BD that take lithium during pregnancy, except for an impact on newborn Apgar scores. Lithium might be an adequate treatment for pregnant women with BD, especially for those with a high recurrence risk, and always after an individualized risk-benefit assessment.