Weigh fetal exposure risks against undertreating: the impact of prenatal exposure to untreated mental illness should not be underestimated.(Obstetrics)

TORONTO -- Physicians weighing the risks versus benefits of medicating nonobstetric conditions during pregnancy should consider that their dilemma is not one of fetal exposure versus nonexposure, according to Dr. Zachary N. Stowe, a psychiatrist and director of the Women's Mental Health Program at Emory University, Atlanta.

"You expose the fetus to something, be it illness or the treatment," he said at the annual meeting of the Society for Gynecologic Investigation. And amid the growing evidence of risks associated with prenatal exposure to antidepressants is the danger of losing sight of alternative risks, he said.

"Of concern to me is that often, the treatment of mental illness is viewed as more 'optional' than, for example, [the treatment of] epilepsy, hypertension, or infection--despite the fact that there are considerably more data demonstrating that maternal depression and anxiety may have more severe sequelae, particularly with respect to child development," Dr. Stowe said in an interview.

The impact--both short and long term--of prenatal exposure to untreated mental illness should not be underestimated, he warned. Studies show that low birth weight (LBW), small for gestational age (SGA), and preterm delivery are linked with untreated major depression and anxiety disorders. Untreated schizophrenia is also linked with LBW and SGA, as well as stillbirth and increased infant mortality.

Moreover, untreated eating disorders are associated with LBW and preterm delivery. In the long term, prenatal exposure to untreated major depression has been linked to motor delays, reactivity, attention problems, and EEG alternations in offspring. And untreated anxiety disorders are associated with conduct disorder and increased anxiety in offspring, said Dr. Stowe, who acknowledges receiving research grants and serving on the speakers' bureaus of "most pharmaceutical companies" that make antidepressants.

Even with medication, depression relapse rates are higher in pregnancy than among nonpregnant women. In a recent prospective study of 201 women with major depression, Dr. Stowe and his colleagues showed a 26% relapse rate among those who maintained their medication until delivery. Women who discontinued their medication had a relapse rate of 68% (JAMA 2006;295:499-507).

Dr. Stowe emphasized that his group's recent review of the literature shows that in almost 17,000 cases of prenatal antidepressant exposure, the highest malformation rate associated with a particular antidepressant is 3.5%. That was the rate found for paroxetine (Paxil).