Diav-Citrin O, et al. - A prospective comparative observational cohort study was undertaken to determine the rate of major anomalies after first trimester (T1)-metformin exposure. Researchers prospectively followed-up 170 T1-metformin-exposed pregnancies [119 for diabetes and 51 for polycystic ovary syndrome (PCOS)] and compared them with 93 pregnancies of T1-insulin treated women and 530 non-teratogenic exposed (NTE) pregnancies. No association of metformin first-trimester exposure with a teratogenic risk was observed. The groups with diabetes demonstrated the pattern of anomalies that could be related to hyperglycemia.