Birth-Control Devices

Birth-control devices are designed to prevent fertilization from taking place. Some, such as condoms, diaphragms, contraceptive sponges, and cervical caps, provide a physical barrier that keeps sperm and egg from coming into contact. Others are chemical methods: birth-control pills contain hormones that change the lining of the uterus to prevent implantation, prevent a woman’s ovaries from releasing mature eggs, or thicken the cervical mucous to prevent sperm from entering; spermicidal creams and gels kill the sperm directly. An intrauterine device (IUD) is thought to interfere with the implantation of the egg in the lining of the uterus.

Dorling Kindersley

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Birth Control

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