Progestin-only injectables may help to prevent pelvic inflammatory disease. A WHO multinational study of 319 women with PID and 638 matched controls found that the risk of acute PID among DMPA or NET EN users was half that among nonusers, although the difference in risk was not significant because of the small sample (99). Injectables may protect against PID by thickening cervical mucus, preventing STD organisms from passing through the cervix.

Progestins have decreased the frequency of seizures in women with epilepsy (194, 359). Several studies have reported that the frequency of seizures in women decreases when progesterone levels are high during the menstrual cycle and increases when estrogen levels are high. In one study of 14 women who added oral and injected medroxyprogeterone acetate to their antiepileptic drugs for an average of 12 months, the frequency of seizures among 11 women who developed amenorrhea declined by 30%, from eight seizures per month before the addition to five after, a significant change (194).

Endometriosis causes painful menstruation and prolonged bleeding. Oral medroxyprogesterone at 20 to 30 mg a day is used to treat endometriosis (214). Clinical observation suggests that DMPA at the contraceptive dose decreases symptoms as well (154).