Pregnant women worried about taking a drug for depression may be relieved by the results of a study showing that the most common antidepressants do not harm the nervous systems of the developing baby.
According to the researchers, this is the first study to demonstrate the safety of older antidepressants (tricyclic agents), as well as fluoxetine (Prozac) taken during pregnancy.
"Exposure to either type of drug throughout gestation did not affect the IQ or language and behavioral development of the offspring as measured during the preschool years." write the researchers in an article published this week in The New England Journal of Medicine.
The study, conducted in Canada, evaluated 80 children of mothers who used tricyclic antidepressants during pregnancy, 55 whose mothers took Prozac, and a group of 84 youngsters whose mothers had not used any drug or chemical known to cause birth defects during pregnancy. The children tested were between the ages of 16 months and about 7 years.
"We found that on language, IQ, and other behavioral tests we were able to do, that we were unable to demonstrate any differences between the three groups," says study co-author Dr. Donna E. Stewart, chief of women's health at Toronto Hospital.
"Basically, it would appear that these drugs do not have any adverse effect on neurodevelopment in children when they're exposed in utero," she adds.
Stewart, who also is a professor on the faculty of medicine at the University of Toronto, notes that the study found no significant differences between the groups of youngsters in temperament, mood, arousability, activity level, distractibility, or behavior problems.
But despite the findings, Stewart remains cautious.
"I think it bears emphasizing that IQ and language development tests are not totally reliable at this young age," she says. "And that to be absolutely certain, one wants to keep track of these children until the age of 10, 12, 14. But insofar as the study goes, I think it's very encouraging news for women who require antidepressants during pregnancy, or those who became pregnant at the time they were on the medication."
"These women can be reassured that as best we can tell, these drugs don't have an effect on IQ and language development," the researcher adds.
Previous studies have suggested a possible link between antidepressants taken during pregnancy and birth defects. Among these was a report tying Prozac to major congenital malformations. But according to the Toronto researchers, these studies failed to consider the mother's lifestyle behaviors that might also be linked to birth defects -- cigarette smoking, alcohol consumption, and use of other drugs.
"We were able to control for alcohol, cigarette use, other drug use, socioeconomic status, and mother's IQ," says Stewart. "So we were fairly careful in screening for the known things that might affect (the risk of birth defects)."
SOURCE: The New England Journal of Medicine (1997;336:258-262)