To stay well, pregnant women may need higher doses of a medication commonly used to treat bipolar disorder.
A new study published in American Journal of Psychiatry shows the blood concentration of the drug lamotrigine decreases in pregnant women.
About half of the women in the study had worsening depressive symptoms as their lamotrigine blood levels dropped. The drug levels fall because women have increased metabolism during pregnancy.
When a woman with bipolar disorder becomes pregnant, she and her physician often don’t realize her medication needs adjusting to prevent the symptoms from coming back—a higher risk during pregnancy. There also is little information to guide dosing for psychiatric medications during pregnancy, researchers say.
Approximately 4.4 million women in the US have bipolar disorder. Women of childbearing age having the highest prevalence.
Proactive treatment needed
“Now physicians change the dose of the drug in response to women’s symptoms worsening,” says lead investigator Crystal Clark, assistant professor of psychiatry and behavioral sciences at Northwestern University Feinberg School of Medicine and a psychiatrist at Northwestern Memorial Hospital. “We need to optimize their medication dosing so they stay well.”
The study results will help physicians understand how to increase their patients’ doses during pregnancy and then reduce them postpartum to avoid toxicity, Clark says.
Depressive episodes—as opposed to manic—are most likely to recur in pregnant women with bipolar disorder.
“The safety of the fetus is at risk,” Clark says. “Pregnant women that are depressed are less likely to take care of themselves, which often leads to poor nutrition, lack of compliance with prenatal care, and isolation from family and friends.
“It has also been linked to premature births and babies with low birth weights among other poor birth outcomes.”
The National Institute of Mental Health of the National Institutes of Health supported the research.
Source: Northwestern University