Lithium dosing strategies during pregnancy and the postpartum period

Abstract

<b>Background</b>Lithium is challenging to dose during pregnancy.<b>Aims</b>To provide guidance for dosing lithium during pregnancy.<b>Method</b>Retrospective observational cohort study. Data on lithium blood level measurements (<i>n</i> = 1101), the daily lithium dose, dosing alterations/frequency and creatinine blood levels were obtained from 113 pregnancies of women receiving lithium treatment during pregnancy and the postpartum period.<b>Results</b>Lithium blood levels decreased in the first trimester (-24%, 95% CI -15 to -35), reached a nadir in the second trimester (-36%, 95% CI -27 to -47), increased in the third trimester (-21%, 95% CI -13 to -30) and were still slightly increased postpartum (+9%, 95% CI +2 to +15). Delivery itself was not associated with an acute change in lithium and creatinine blood levels.<b>Conclusions</b>We recommend close monitoring of lithium blood levels until 34 weeks of pregnancy, then weekly until delivery and twice weekly for the first 2 weeks postpartum. We suggest creatinine blood levels are measured to monitor renal clearance.