TUESDAY, April 3 (HealthDay News) -- Infants born to mothers who take antipsychotic medications during pregnancy have significantly lower than normal scores on a standard test of movement, posture and reflexes, a new study has found.

Antipsychotic drugs often are used in the treatment of schizophrenia and bipolar disorder.

Researchers from Emory University in Atlanta compared the neuromotor skills of more than 300 infants at age 6 months. Some of the babies' mothers took either antipsychotic drugs or antidepressants during pregnancy, and some took no psychiatric medications.

Infants born to mothers who took antipsychotics had much lower scores on the neuromotor test than those born to mothers who took antidepressants or no psychiatric medications. Only 19 percent of infants exposed to antipsychotic medications had normal test results.

"Future investigations are warranted to disentangle the relative contribution of antipsychotic medications, maternal mental illness, [associated] medications and the broader psychosocial context in the developmental trajectory of high-risk infants," study author Katrina Johnson, a clinical psychologist at Emory, and colleagues said in a journal news release.

"Pending such studies, these data support an additional level of scrutiny in medication selection, treatment planning and risk/benefit discussions for women with illnesses who may warrant antipsychotic [therapy] during gestation," the researchers said.

About two-thirds of women with a history of mental illness give birth, but there has been little research into the safety and effectiveness of giving these women psychiatric medications when pregnant, the researchers noted.

The study did not prove that antipsychotic drugs caused motor-skill delays; it merely showed an association.

The study appears online April 2 in the journal Archives of General Psychiatry.

More information

The U.S. Department of Health and Human Services Office on Women's Health has more about pregnancy and medicines.