Women with a history of bipolar disorder or postpartum psychosis are at extremely high risk of relapse postpartum. Although lithium prophylaxis has demonstrated efficacy in reducing postpartum relapse, the timing of prophylaxis remains controversial given the balance of risks and benefits for the mother and fetus. The authors compared lithium use during pregnancy compared to its initiation postpartum in women at high risk for postpartum psychosis.

Between 2003 and 2010, 70 pregnant women at high risk for postpartum psychosis were referred to the authors'psychiatric outpatient clinic. Women who were initially medication-free were advised to start lithium prophylaxis immediately postpartum. Women already taking maintenance lithium during pregnancy were advised to continue treatment.

All women with a history of psychosis limited to the postpartum period (n=29) remained stable throughout pregnancy despite being medication-free. Of the women with bipolar disorder (n=41) 24.4% relapsed during pregnancy, despite prophylaxis use by the majority throughout pregnancy. The postpartum relapse rate was highest in women with bipolar disorder who experienced mood episodes during pregnancy (60.0%). In contrast, none of the 20 women with postpartum psychosis using postpartum prophylaxis relapsed, compared to 44.4% of postpartum psychosis patients who declined prophylaxis.

The authors recommend initiating prophylactic treatment immediately postpartum in women with a history of psychosis limited to the postpartum period, to avoid in utero fetal exposure to prophylactic medication. Patients with bipolar disorder require continuous prophylaxis throughout pregnancy and the postpartum period to reduce peripartum relapse risk.