ix21@sdccs6.UUCP (04/27/84)
There has been a lot of articles posted recently about oral contraceptives containing incorrect information. I hope my posting clears up the confusion. My references include the 1984 Physicians' Desk Reference and Goodman and Gilman's The Pharmacological Basis of Therapeutics. The original oral contraceptive, consisting of an estrogen and a progestin has been attributed to have an effectiveness so close to 100% "that a closer estimate can not be made." These preparations containing more than 50 micrograms of mestranol or 35 micrograms of ethinyl estradiol interfere with the timing of the secretions of LSH and FH from the pituitary gland, such that ovulation is prevented. [denecor!neal states that these pills are no longer used -- they are still used but not widely.] Since the estrogen is believed to cause most of the side-effects of the pill, other formulations with less estrogens are used; these preparations have an effectiveness of about 98 to 99%. The minipill contains only a progestin "it works in part by preventing release of an egg from the ovary but also by keeping sperm from reaching the egg and by making the uterus (womb) less receptive to any fertilized egg that reaches it." This preparation is 97% effective. Ovulation occurs in forty percent of the cycles of a woman taking this type of pill. ihuxi!walsh asks how can just decreasing the amount of hormone can stop implantation and not ovulation; the uterus is just more sensitive to changes of hormone levels than the ovaries. Another person said that this fact was kept a secret by physicians for a long time and only recently released; the above quote comes from the insert which is placed in every minipill package for the user to read. There also exists a morning-after pill which is actually a series of pills taken twice daily for five days each containing 25 mg. of an estrogen; note that the amount of estrogen in other contraceptives is measured in micrograms. The expected side-effects include nausea and vommiting. Many doctors believe that not taking the morning-after pill but performing an abortion later if necessary is safer. Finally one person says the IUD works only by prevention of implantation; there is considerable evidence that an IUD prevents the muscular contractions that allow the sperm to migrate through the uterus to the ovum. I hope that this information has been useful or at least read.