were made of metal and were held inby prongs. Later, wire rings were placed beyondthe cervix, in the uterus itself, thus giving rise to theterm intrauterine device, or IUD. IUDs appear towork by altering the necessary environment in theuterus for the fertilized egg. It was only with theintroduction of modern plastics such aspolyethylene, however, that IUDs were widelyaccepted. Their pliability led to simpler insertiontechniques, and they could be left in place untilpregnancy was desired unless a problem arosewith their use. Copper-containing IUDs, and thosethat slowly released the hormone progesterone,had to be replaced periodically. Some users ofIUDs, however, complained increasingly of theside effects of the devices. The most commonproblem was bleeding, and the devices could alsocause uterine infections. More dangerous was thepossible inducement of pelvic inflammatorydisease (see UROGENITAL DISEASES), aninfection that may lead to blockage of theFallopian tubes and eventual sterility or an ectopicpregnancy. Studies in the 1980s confirmed thislink with the increased risk of infertility even in theabsence of apparent infections, especially withplastic IUDs. The A. H. Robins Company, inparticular, was ordered in 1987 to set aside nearly$2.5 billion to pay the many thousands of claimsfiled against it by women injured through use of itsDalkon Shield. By that time only a single,progesterone-releasing IUD remained on the U. S.market, but a copper IUD later became availableand other steroid releasing devices were beingplanned for issue. The birth control pill, taken oncea day, has become the most popular birth controlmethod among American women. Oralcontraceptives are similar in composition to thehormones produced naturally in a woman's body.Most pills prevent ovaries from producing eggs.Use of the pill, however, does not preventMENSTRUATION; usage may even causeperiods to be more regular, with less cramps andblood loss. Recent studies seem t...
