Use of second-generation antipsychotic medications during the first trimester of pregnancy does not significantly raise the chance of fetal malformations, according to the findings of a new study from the American Journal of Psychiatry.
“The present findings challenge the frequently observed clinical practice of abruptly stopping maintenance treatment for psychiatric disorders during pregnancy,” according to Lee Cohen, MD, of Massachusetts General Hospital in Boston, and colleagues who analyzed data from the National Pregnancy Registry for Atypical Antipsychotics.
Researchers established the registry in 2008 to obtain reproductive safety data on fetal exposure to second-generation (also called atypical) antipsychotic medications.
Cohen and colleagues examined medical records and pregnancy outcomes for 214 pregnant women exposed to second-generation antipsychotic medications during their first trimester of pregnancy and 89 pregnant women who were not exposed to the medications during their pregnancies.
The comparison group mostly consisted of women with a history of psychiatric illness being treated with a variety of psychotropic medications other than second-generation antipsychotics, including selective serotonin reuptake inhibitors, anticonvulsants, and anti-anxiety medications. The most commonly used antipsychotic medications in the registry were quetiapine (Seroquel), aripiprazole (Abilify), and olanzapine (Zyprexa).
A major malformation was defined for the purposes of the study as a structural abnormality with surgical, medical, or cosmetic importance.
Of the 214 pregnancies exposed to atypical antipsychotic medications, three major malformations were recorded, versus one in the comparison group of 89 pregnancies with no exposure to antipsychotic medications. Other classes of medication were used in the mothers of the three infants with major malformations in the exposed group, the authors noted.
These outcomes translated to an absolute risk of major malformations of 1.4% for exposed infants and 1.1% for no exposure, and in turn to an odds ratio of 1.25 (95% CI 0.13-12.19).
Study limitations include the small sample size, the heterogeneity of the sample — the majority of women were white, married, and college-educated. In addition, according to the report, “with only four identified malformations, the statistical power to identify risk factors is low, as illustrated by the wide confidence interval around the odds ratio.”
As a result, the authors could not identify the risk factors that may affect the relationship between second generation antipsychotic use during the first trimester of pregnancy and major malformations in utero.
Cohen told MedPage Today that a goal for further research will be to seek to analyze results from larger numbers of exposed subjects and controls “so that we can make estimates of risk with greater confidence for the class of medicines and also for individual medications.”
He said that as the pregnancy registry continues to expand and the sample grows, there will be follow-up reports, “but so little is known about these medicines and their use in pregnancy, we decided to publish these preliminary /current findings to at least provide some guidance to the clinician.”