[Postcoital contraception (without prostaglandins)]

PIP: Postcoital contraception, or "interception" of the blastocyte before it implants in the uterus, is an effective method of contraception which is recommended for more frequent use, though only as indicated in emergencies such as rape, rupture of condom, 1st sexual experience without contraception, and isolated sexual relations without contraception. General contraindications include already existing pregnancy and multiple risk of pregnancy in a single menstrual cycle. There are 3 types of accepted hormonal postcoital contraception--estragens alone, progestagens alone, and combined estrogen and progestagen-- which must begin within 48-72 hours after intercourse. Estrogens most commonly suggested are 1) diethylstilbestrol (DES), 50 mg daily for 5 days, 2) conjugated estrogens, 10 mg daily for 5-6 days, and 3) ethinyl estradiol (EE), 5 mg daily for 5 days. The high dosages required for effectiveness can cause complications, the most severe being ectopic pregnancy, but the failure rate of this method is only .7%. The failure rate using progestagens alone is inversely proportional to the administered dose (i.e., 1% for 1 mg of D-norgestrel or levonorgestrel). Norgestrel and quingestanol are used most frequently with the most severe complication being disturbance of the cycle. Oral administration of the combination pill containing .05 mg EE and .25 mg D-norgestrel, at a 12-hour interval is the most widely accepted hormonal method, as the short treatment period assures patient compliance, the low estrogen dosages reduce the occurrence of side effects, although 40-50% still experience nausea, and the contraindications are the same as for general estrogens-progestagens. Intrauterine postcoital contraception involves insertion of a coil, which prevents implantation of the blastocyte in the uterus, and has been shown to be 100% effective, although no extensive series have been publicized as compared with the hormonal methods. Where postcoital contraception is used, a detailed history should be obtained to determine risk of pregnancy and possible contraindications, and the patient should be informed of the side effects and procedural methods.

PMID: 6489843 [PubMed - indexed for MEDLINE]