PITTSBURGH — Pregnancy can trigger a relapse in women with bipolar disorder, especially if they stop their mood-stabilizing treatment.
Although data from several studies are conflicting, a prospective study showed that about two-thirds of women with a history of bipolar disorder had a relapse during pregnancy, Adele C. Viguera, M.D., said at the Sixth International Conference on Bipolar Disorder.
In that study, about half of the women had relapsed before their 18th week of pregnancy. Relapse was even more rapid in the postpartum period, with about half of the women studied having a return of their bipolar disorder within 6 weeks after delivery, said Dr. Viguera, of the department of psychiatry at Massachusetts General Hospital in Boston.
Results from a separate study, led by Dr. Viguera and reported 2 years ago, showed that the majority of bipolar recurrences during pregnancy or postpartum involve either major depressive episodes or mixed states.
A major factor linked with recurrences is discontinuation of mood-stabilizing treatment, especially an abrupt stop. In Dr. Viguera's study which involved 82 women, the relapse rate among the women who stopped their mood-stabilizing medication was 75%, compared with a 35% relapse rate among women who continued their treatment.
Another important determinant of relapse is whether affective illness occurs during pregnancy. In Dr. Viguera's study, a total of 61% of the studied women had a postpartum relapse. More than 80% of the women with relapses had affective illness during pregnancy. As a result of this observation, “we're very aggressive about maintaining euthymia” during pregnancy, Dr. Viguera said at the meeting, also sponsored by the University of Pittsburgh.
But data are limited on the safety of mood stabilizers during and after pregnancy. A study reported this year showed that in a North American registry, treatment of pregnant women with valproic acid was linked with 16 fetal anomalies among 149 women treated, an 11% rate that was “much higher than expected,” said Dr. Viguera. Additional findings from studies of valproic acid use in pregnant women with epilepsy also show a relatively high rate of major malformations, fetal death, and developmental delay.
Results from another registry showed that treatment with lamotrigine was associated with a 3% incidence of major malformations in a series of 414 treated women. Other studies have confirmed that lamotrigine treatment is linked with fewer serious effects during pregnancy than other anticonvulsants.
Results from a prospective study published this year showed a single major malformation among 151 women treated with an atypical antipsychotic in pregnancy. The drugs included in this study were olanzapine, risperidone, quetiapine, and clozapine. Although the low rate of fetal damage was reassuring, the number of women studied was too small to produce a definitive conclusion about safety, Dr. Viguera said.