"Over the last couple of decades a reduction of estrogen by at least 80% in combined oral contraceptives (OCs) and much research have resulted in effective and safe contraception. We still do not know longterm effects of OCs however. OCs may protect against endometrial and ovarian cancer. A link between current OC use and liver cancer exists in areas where liver cancer is rare. An association between OC use and cervical cancer disappears when researchers control for sexual activity and barrier method use. Some research shows OC use increases the risk of breast cancer, while other research does not. There does appear to be an increased risk of breast cancer developing in women younger than 46 years of age and who have used OCs for at least 10 years. Women who have a preexisting cardiovascular condition and/or smoke should not use OCs. OC progestogens may impair glucose metabolism in healthy women, but just for 6 months. Women with diabetes mellitus can use OCs, but may need to increase insulin intake. OCs can cause hypertension in 4-5% of healthy women and worsen hypertension in about 9-16% of hypertensive women. Progestogen-only OCs have fewer systemic side effects than combined OCs, but often cause menstrual changes. Their long term effects are not yet known. Injectables containing a progestogen cause few, if any, adverse effects. The subdermal implant, Norplant, tends to cause menstrual disturbances, but is safe and effective. Progestogen - only vaginal rings are as effective as progestogen-only OCs, but menstrual irregularities are common. Failure rates for combined vaginal rings match those of combined OCs. Long-term effects of vaginal rings are not known. Postcoital contraception does not cause serious side effects, but may cause vomiting and menstrual irregularities. A levonorgestrel-releasing IUD is effective and reduces menstrual blood loss, sometimes resulting in amenorrhea. Hormonal injections in men are unlikely in the near future."