An obstetrician-gynecologist (OB-GYN) is a medical doctor specializing in both obstetrics and gynecology. Obstetrics focuses on pregnancy, childbirth, and postpartum care, while gynecology deals with the female reproductive system. OB-GYNs provide a wide range of services for women’s health, including routine check-ups, diagnosis and treatment of gynecological conditions, and delivery of babies.