Backgrounds: To improve health, an increasing number of adults are attempting to lose weight. Moreover, the number of childbearing women targeting weight loss has increased, with a surge in pregnant women exposed to anti-obesity drugs. This study aimed to evaluate the ingredients, types, and trends of anti-obesity drugs and pregnancy outcomes among the exposures of anti-obesity drugs. Additionally, we reviewed their teratogenicity in literature. Methods: We performed a prospective cohort study and recruited pregnant women exposed to anti-obesity drugs in the Motherisk Database, from 2012 to 2018. We determined the frequency and type of anti-obesity drugs used. Furthermore, we compared the annual change in the frequency of anti-obesity drugs with that of total pregnancies. Overall, 30,704 pregnant women were enrolled during the study period. Results: The rate of pregnant women exposed to anti-obesity drugs was 4.8% (1487/30,704). The rate of pregnant women exposed to anti-obesity drugs significantly increased from 3.7% in 2012 to 7.4% in 2018 (p 0.001). The most frequently used drugs were phentermine (33.0%) and phendimetrazine (25.9%). The number of pregnant women exposed to anti-obesity drugs has recently increased. There is no difference in pregnancy outcomes between the exposure and the un-exposure of anti-obesity drug except that birth weight and large for gestational age are significantly larger in the exposure group. Additionally, there are no difference of abnormalities between the exposure (3.1%) and the un-exposure of anti-obesity drugs (3.7%). Discussion: This study showed that the exposure of anti-obesity drug profoundly increased during the study period and there exist known teratogenic drugs. Therefore, childbearing women should be concerned with preventing teratogenic effects following anti-obesity drug exposure during pregnancy. Physicians should warn childbearing women about potential dangers of anti-obesity drug.