Small observational study: fluvoxamine not linked to rise in fetal malformation risk

OB/GYN News, May 1, 2004 by Diana Mahoney

MIAMI -- The use of fluvoxamine in pregnancy is not associated with an increased risk of major fetal malformations, according to preliminary results of an ongoing observational study.

Investigators compared the pregnancy outcomes of 46 women taking the selective serotonin reuptake inhibitor to treat depression with those of 46 women taking established nonteratogenic products for the same condition. Anna Sivojelezova reported in a poster presentation at the annual meeting of the American Society for Clinical Pharmacology and Therapeutics.

Fetal survival rates, birth weight, and rates of major malformations did not differ significantly between the two groups. In both groups, "we observed two major fetal malformations," said Ms. Sivojelezova of the Hospital for Sick Children in Toronto.

There were no significant differences in pregnancy outcomes between women who took fluvoxamine (Luvox) throughout pregnancy and those who took it only during the first trimester, she noted.

Because of the study's small sample size, a small increased risk for rare birth defects cannot yet be ruled out, said Ms. Sivojelezova, who, along with her colleagues, is currently recruiting more women for the study.

Currently a Food and Drug Administration category C drug in pregnancy, fluvoxamine is of particular interest because it was the first antidepressant approved by the FDA for obsessive-compulsive disorder, and it is the number one drug prescribed by psychiatrists for this disorder, Ms. Sivojelezova stated.

Because of the high incidence of depression and obsessive-compulsive disorder in women of childbearing age--and because as many as half of all pregnancies are unplanned--information on the safety and efficacy of this drug in pregnancy is necessary to help physicians in pregnancy risk assessment, she stressed.

Ms. Sivojelezova and her associates recruited participants for the study from a list of pregnant women who contacted the hospital's Motherisk Program with questions about the safety of fluvoxamine in pregnancy. Intake coordinators documented participants' medical and obstetric histories, and followed up with a telephone interview after the expected date of delivery. All of the women exposed to fluvoxamine were matched to the control group for disease, age, time of first call to Motherisk, and smoking and drinking habits.

The 4.3% risk of major malformations observed in both the exposed and control groups is within the range for baseline risk (1%-5%) observed in the general population.

BY DIANA MAHONEY

New England Bureau