contraceptive

Any drug, device, or technique that prevents pregnancy. The contraceptive pill (the Pill) contains female hormones that interfere with egg production or the first stage of pregnancy. The ‘morning-after’ pill can be taken up to 72 hours after unprotected intercourse. Barrier contraceptives include condoms (sheaths), diaphragms, and sponges; they prevent the sperm entering the cervix (neck of the womb).

Intrauterine devices, also known as IUDs or coils, cause a slight inflammation of the lining of the womb; this prevents the fertilized egg from becoming implanted. See also family planning.

Other contraceptive methods include sterilization (women) and vasectomy (men); these are usually nonreversible. ‘Natural’ methods include withdrawal of the penis before ejaculation (coitus interruptus), and avoidance of intercourse at the time of ovulation (rhythm method). These methods are unreliable and normally only used on religious grounds. The use of any contraceptive (birth control) is part of family planning. The effectiveness of a contraceptive method is often given as a percentage. To say that a method has 95% effectiveness means that, on average, out of 100 healthy couples using that method for a year, 95 will not conceive.