Very little is known about the effects upon, or risks to (if any), the developing embryo/fetus/baby, as a result of risperidone or clozapine taken during pregnancy (see Altshuler et al, Am J Psychiatry, for a good review of psychotropic medications and pregnancy). The manufacturer of risperidone notes that there are no well-controlled studies in pregnant women, though they cite one report of a case in which an infant exposed to risperidone in utero was missing the corpus callosum (a nerve tract in the brain). It is almost impossible to know if this was “caused” by the risperidone, however. It is also not known if risperidone is excreted in breast milk, though it is in animal studies.
There is somewhat more information about clozapine, but not much. Data from animal studies suggest that clozapine has a low risk of causing fetal abnormalities, but no adequate studies in pregnant women have been done. As of Waldman & Safferman’s 1993 report in the January 1993 American Journal of Psychiatry, there were at least 15 cases of normal births following maternal exposure to clozapine – this seems encouraging, but the numbers are far too small to permit meaningful conclusions. There is evidence (Barnas et al, Am J Psychiatry June 1994) that clozapine does enter the fetal circulation prior to birth and also via breastfeeding. This could cause sedation and decreased muscle tone in the neonate, and dosage should probably be kept low in the days that precede delivery.
All these potential problems with antipsychotics during pregnancy should not obscure the very substantial risks to both mother and developing child if the mother’s psychosis is not well-controlled during pregnancy, as Altshuler et al point out. While ECT is sometimes a good alternative, there are few compelling reasons, in general, to discontinue antipsychotic medication during pregnancy when the patient’s mental stability is at stake.