Gynecology is the branch of medicine and surgery specializing in diseases of women, specifically disorders of the female reproductive tract; it is often linked with obstetrics. Contraception, abortion, sterilization, infertility, and abnormalities of menstruation are the commonest problems. The early recognition and treatment of cancer of the uterus and cervix after papanicolaou ("pap") smears have become important. Other tumors of the uterus (womb) and ovaries, benign or malignant, and disorders of the genital tract or bladder following pregnancy, commonly require gynecological surgery. Dilation of the cervix and curettage of the womb endometrium (D and C) is used frequently for diagnosis and sometimes for treatment of menstrual disorders or postmenopausal bleeding. Hysterectomy or removal of the womb is the commonest major operation of gynecologists.