Pregnant women can take lithium safely for control of bipolar disorder as delivery approaches during late pregnancy provided they follow a series of guidelines designed to minimize risk to the developing fetus, according to Emory University School of Medicine researchers writing in a recent issue of the "American Journal of Psychiatry."
Maintaining a therapeutic dose of lithium until right before delivery can help pregnant women avoid symptoms of bipolar disorder without posing undue risks of harm to the fetus, says a team of researchers led by D. Jeffrey Newport, MD, MS, MDiv, assistant professor of psychiatry at the Emory University School of Medicine and associate director of the Emory Women's Mental Health Program. Co-author Zachary N. Stowe, MD, is an associate professor of psychiatry at Emory and serves as the program's director.
The Women's Mental Health Program is dedicated to the research and treatment of mental illness during pregnancy and the postpartum period. The study, which followed women receiving care through the program, is described in the November 2005 issue of the journal.
Bipolar disorder is equally distributed among men and women, and affects about 1 percent of the population. In both men and women, it is most likely to appear in the early twenties -- significantly, a woman's most common child-bearing years.
Given the risk of untreated bipolar disorder to both the woman and her child, the Emory researchers conclude that "prolonged discontinuation of treatment is seldom a viable option" and that lithium remains the "preferred alternative" for many women during gestation.
"Left untreated, women with bipolar disorder do not do well during pregnancy and are particularly vulnerable during the postpartum period," explains Dr. Newport. "Prolonged suspension of mood stabilizer treatment does not work well for most women."
Since the 1950s, lithium has been the cornerstone for treatment of bipolar disorder, and discontinuing the drug poses a series of mental health risks. Preliminary data indicate that pregnant women who discontinue lithium treatment for bipolar disorder run a greater than 80 percent likelihood of relapse during pregnancy. A woman with bipolar disorder is 100 times more likely than the background rate -- 0.05 percent -- to suffer postpartum psychosis.
However, maintaining therapeutic lithium levels in the mother can pose risks to the newborn infant. In the current study, Emory researchers confirmed that lithium levels in the mother and fetus were statistically the same at delivery, suggesting the drug readily passes from mother to fetus across the placental barrier. High lithium exposure, was associated with a consistently higher rate of neonatal complications, particularly central nervous system and neuromuscular complications.
Although the complications associated with lithium compare favorably to those of other mood stabilizers, its risks to a newborn are well-documented. Among these are cardiac dysfunction, diabetes insipidus, low muscle tone and respiratory difficulties. Based on previous research, the Emory researchers speculate that such difficulties are related to lithium exposure during delivery and can be reduced or eliminated by briefly suspending maternal lithium administration near delivery.