Wellbutrin (bupropion) is manufactured by GlaxoSmithKline and was first approved by the FDA as an antidepressant in December 1985. Researchers are warning patients about serious side effects from using Wellbutrin. Results from a recent medical study suggest that there may be an increased risk of heart birth defects from Wellbutrin when the antidepressant is taken during pregnancy. Mothers who used bupropion during their first trimester were more than twice as likely to give birth to an infant with a congenital heart problem known as a left outflow tract defect. Researchers cautioned that the study does not draw a cause-and-effect relationship between Wellbutrin and birth defects, and further research is necessary.