gynecology and obstetrics
Emergency Contraception
Introduction
Emergency contraception may be used to prevent pregnancy for a short period of time after unprotected sex. Commonly used emergency contraception methods include Insertion of anintrauterine copper contraceptive(T380A IUD) within 5 days of unprotected intercourse Insertion of a 52-mglevonorgestrel-releasing IUD, which, like thecopperIUD, probably requires insertion within 5 days of unprotected intercourse Levonorgestrel1.5 mg orally once within 120 hours of unprotected intercourse Ulipristal30 mg orally once within 120 hours of unprotected intercourse For women who have regular menses, the risk of pregnancy after a single act of intercourse is approximately 5%. This risk is 20 to 30% if intercourse occurs at midcycle. -releasing IUD ( General reference ). Also, the IUD can be left in place to be used for long-term contraception. As emergency contraception, the Orallevonorgestrel(1.5 mg, single dose) used as emergency contraception prevents pregnancy by inhibiting or delaying ovulation. The probability of pregnancy is reduced by 85% after orallevonorgestrelemergency contraception, which has a pregnancy rate of 2 to 3%. However, overall risk reduction depends on the following: The woman's risk of pregnancy without emergency contraception The time in the menstrual cycle that emergency contraception is given The woman's body mass index (BMI;levonorgestrelemergency contraception is less effective thanulipristalin women with a BMI > 30 kg/m2) In the United States, orallevonorgestrelemergency contraception is available behind pharmacy counters without a prescription. A hormonal contraceptive may be started at the same time as use of orallevonorgestrelas part of a quick-start protocol. A backup method (such as a condom) is recommended for 7 days. Ulipristal(a single oral dose of 30 mg), aprogestin-receptor modulator, as emergency contraception has a pregnancy rate of about 1.5% and is thus more effective than orallevonorgestrel.Ulipristal, likelevonorgestrel, prevents pregnancy primarily by delaying or inhibiting ovulation. Althoughulipristalis more effective thanlevonorgestrelfor women with a BMI > 30 kg/m2, its effectiveness also decreases as BMI increases. Thus, in women who are obese who strongly desire to avoid an unintended pregnancy, thecopperIUD is the preferred method for emergency contraception.Ulipristalis available by prescription only. Hormonal birth control should not be started until 6 days after use ofulipristal, sinceprogestinsmay interfere with emergency contraceptive efficacy. If hormonal contraception is started on day 6, a backup method (such as a condom) should be used for 7 days. There are no absolute contraindications tolevonorgestrelorulipristalemergency contraception. Orallevonorgestrelandulipristalemergency contraception should be taken as soon as possible and within 120 hours of unprotected intercourse. TheYuzpe methodis another regimen. It consists of 2 tablets, each containing ethinylestradiol50 mcg andlevonorgestrel0.25 mg, followed by 2 more tablets taken 12 hours later but within 72 hours of unprotected intercourse. The highestrogendose often causes nausea and may cause vomiting. A hormonal contraceptive may be started at the same time as use of the Yuzpe method, as part of a quick-start protocol. A backup method (such as a condom) is recommended for 7 days. The Yuzpe method is less effective than other methods; thus, it is no longer recommended except when women do not have access to other methods. A urine pregnancy test 2 weeks after use of emergency contraception is recommended. 