Obstetrician-gynecologists specialize in the general medical care of women, as well as care related to pregnancy and the reproductive tract. The obstetrician-gynecologist goes through four years of specialized residency training in areas dealing with preconception health, pregnancy, labor and childbirth, postpartum care, genetics, genetic counseling and prenatal diagnosis. After residency, a physician may seek certification from the American Board of Obstetrics and Gynecology. To become Board certified, a physician must pass a written test to demonstrate that he or she has obtained the special knowledge and skills required for medical and surgical care of women. An oral examination is given by a team of well-respected national experts; the exam tests the physician's skills, knowledge and ability to treat different conditions. The examiners also review the patients the physician treated during the past year.