Подпись:Withdrawal, or coitus interruptus, was the most popular method of birth control in the mid-1800s. Although the National Survey of Family Growth (see Chapter 2) estimated that only 2.9% of their sample used withdrawal, most researchers believe this was an un­derestimate (Kowal, 2004b). Because many couples don’t consider withdrawal a legiti­mate contraceptive method, they may not report using it (Kowal, 2004b).

How It Works

Withdrawal does not require any advance preparation. A couple engages in sexual in­tercourse; prior to ejaculation, the male withdraws his penis from the vagina. The ejac­ulate does not enter the uterus.

Effectiveness

Effectiveness rates for withdrawal range from 73% (typical use) to 96% (perfect use). Originally, scientists believed that high failure rates with this method were due to sperm contained in the preejaculatory fluid. However, newer research suggests that preejacula­tory fluid has no sperm in it (Kowal, 2004b). Pregnancy can occur, however, if sperm re­mains in the urethra from a previous ejaculation and is not released during urination.