In 1960, Christopher Tietze presented a paper on the “Probability of Pregnancy Resulting from a Single Unprotected Coitus.” He determined that the risk varied between one in 25 and one in 50. Couples who engage in intercourse without contraception find that their motivation to prevent pregnancy rises dramatically the next day. They may choose one of two techniques that are effective in preventing pregnancy. Historically the first postcoital contraceptive was oral ingestion of steroids such as diethylstilbesterol (DES) or ethinyl estradiol (EE). This usage was appropriately called “interception.” Later, combination steroids were recommended for this purpose, thus reducing both dosage and number of days of drug administration.
A second method of interception available to such patients is the postcoital insertion of an IUD. IUD interception eliminates the nausea that sometimes follows ingestion of such drugs as DES, EE, or a combination of estrogen and a progestin. A postcoital IUD probably prevents pregnancy as late as five or even six days after unprotected coitus, while steroids are useful as interceptives for a maximum of 72 hours.
The choice of which method to use depends on medical history, patient’s preference, drug tolerance, the physician’s findings on pelvic and physical examination, and finally on good communication between physician and patient. There is a need for public education about interception, especially for adolescents, who produce the largest number of unplanned and unwanted pregnancies.
KeywordsCarbonic Anhydrase Ethinyl Estradiol Medroxyprogesterone Acetate Emergency Procedure Unprotected Intercourse
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