Unintended pregnancy rates remain high throughout the World and increase the risk of poor maternal and infant outcomes.Most of unintended pregnancies occur in women who were not using contraceptionor who became pregna...Unintended pregnancy rates remain high throughout the World and increase the risk of poor maternal and infant outcomes.Most of unintended pregnancies occur in women who were not using contraceptionor who became pregnant despite the reported use of contraception.Women who have had recent unprotected intercourse including those who have had another form of contraception fail are potential candidates for this intervention.Currently used em-ergency contraceptive methods are pills that contain combined estrogen-progesterone,only progestin,antiprogestins and copper intrauterine devices.The most common form of this type of contraception is oral progestin-only pills(levonorgestrel).The most effective method is copper intrauterine devices followed by anti-progestins and oral progestin-only pills.The major pathogenesis of oral emergency contraceptives is the prevention or delay of ovulation.Although conception is possible on only a few days of the cycle,emergency contraception is offered when indicated without regard to the timing of the menstrual cycle because of uncertainty in the timing of the ovulation.Levonorgestrel and E/P regimes are most effective as soon as possible after unprotected sexual intercourse.A linear relationship has been shown between ef-fectiveness and the time of dose.The effectiveness continues for 120 h,but it is recommended to be used within 72 h after intercourse.Intrauterine devices may prevent pregnancy when 5 d after ovulation.展开更多
文摘Unintended pregnancy rates remain high throughout the World and increase the risk of poor maternal and infant outcomes.Most of unintended pregnancies occur in women who were not using contraceptionor who became pregnant despite the reported use of contraception.Women who have had recent unprotected intercourse including those who have had another form of contraception fail are potential candidates for this intervention.Currently used em-ergency contraceptive methods are pills that contain combined estrogen-progesterone,only progestin,antiprogestins and copper intrauterine devices.The most common form of this type of contraception is oral progestin-only pills(levonorgestrel).The most effective method is copper intrauterine devices followed by anti-progestins and oral progestin-only pills.The major pathogenesis of oral emergency contraceptives is the prevention or delay of ovulation.Although conception is possible on only a few days of the cycle,emergency contraception is offered when indicated without regard to the timing of the menstrual cycle because of uncertainty in the timing of the ovulation.Levonorgestrel and E/P regimes are most effective as soon as possible after unprotected sexual intercourse.A linear relationship has been shown between ef-fectiveness and the time of dose.The effectiveness continues for 120 h,but it is recommended to be used within 72 h after intercourse.Intrauterine devices may prevent pregnancy when 5 d after ovulation.
