This document discusses diabetes mellitus in pregnancy. It defines diabetes and classifies its types. Gestational diabetes is the most common type seen in pregnancy, accounting for 90% of diabetes cases. Pregnancy increases the risk of developing diabetes due to placental hormones that cause insulin resistance. Screening and management of diabetes in pregnancy is important to prevent complications for both mother and fetus such as macrosomia, shoulder dystocia, and preeclampsia. Treatment involves diet, exercise, blood sugar monitoring, and possibly insulin therapy.