 Data Source and Study Cohort 
 
 The study cohort was drawn from the Medicaid Analytic eXtract for 46 U.S. states and Washington, D.C., for the period of 2000 through 2007. The Medicaid Analytic eXtract data set contains individual-level demographic and Medicaid enrollment information, as well as data on all physician services and hospitalizations and the accompanying diagnoses and procedures and all filled outpatient medication prescriptions. The development of our study cohort has been described previously.22 Briefly, we identified all completed pregnancies in women and adolescents 12 to 55 years of age (hereafter, “women”) and linked these pregnancies to liveborn infants. Finally, we required all the women to be eligible for Medicaid, without supplementary private insurance or restricted benefits, from 3 months before the last menstrual period through 1 month after delivery. We excluded pregnancies in which the infant had received a diagnosis of a chromosomal abnormality (1609 pregnancies) and pregnancies in which the mother had been treated with known teratogens during the first trimester (i.e., lithium, antineoplastic agents, retinoids, and thalidomide; 2476 pregnancies). We defined the following exposure categories: any SSRI, paroxetine, sertraline, fluoxetine, tricyclic antidepressants, serotonin–norepinephrine reuptake inhibitors (SNRIs), bupropion, and other antidepressants (Table S1 in the Supplementary Appendix, available with the full text of this article at NEJM.org).
– An estimated 8% to 13% of pregnant woman are on antidepressants, and not without warning: The FDA in 2005 amended antidepressants' labels to indicate that babies born to moms taking them could suffer an increased risk of heart defects. But causation hadn't been proven, and the latest study on the topic indicates those warnings may be baseless. The latest study, published in the New England Journal of Medicine, followed 949,504 pregnant women, 64,389 (6.8%) of whom used antidepressants during the first trimester—the period of the most rapid cell division, when the risk of developing such defects is highest, WebMD explains. What Krista Huybrechts of Brigham and Women's Hospital did differently: She and her team took into consideration factors that could lead to heart defects, like the mother's age and whether she had diabetes. The Boston Herald reports that among babies whose mothers did not take antidepressants, 72.3 per 10,000 were born with a cardiac defect, compared with 90.1 per 10,000 infants whose mothers did. After controlling for risk factors, "there is no evidence to support a substantial increased risk of cardiac malformations overall," says Huybrechts. Still, she cautions that antidepressant use during pregnancy poses a "whole range of other potential adverse outcomes." To wit, one expert pointed to "serious flaws" with the study. For one, it didn't flag miscarriages, which are linked to antidepressants. "It may be that the most severely affected pregnancies are miscarrying," he noted.