Abstract

PIP: Women requesting family planning advice at the Family Planning Clinic at El-Galaa Hospital in Cairo participated in a study investigating some of the main clinicopathological aspects of switching from 1 oral contraceptive to another. The pills were Vestalin M (2.5 mg vinylestrenelone, .1 mg ethinyl estradiol), Vestalin Uno (1 mg vinylestrenelone, .1 mg ethinyl estradiol), Gynovlar (3 mg article says "m" norethisterone acetate, .05 mg ethinyl beta-estradiol), and chlormadinone, .5 mg. Controls used either Vestalin M (68) or Vestalin Uno (55) for 6 months. 24 users of Vestalin M (average 11 months use) switched to Vestalin Uno, thus changing from a higher to lower level of gestagen. 26 users of Vestalin Uno switched to Vestalin M. 3 groups switched from 1 chemical composition to another: 41 Gynovlar users of average 6 months switched to Vestalin Uno, 14 chlormadinone users of average 24 months switched to Vestalin Uno, and 18 chlormadinone users of average 18 months switched to Vestalin M. Post-menstrual endometrial biopsies (cycle days 5-7) were taken before the start of first therapy, before the switch, and at the end of the second drug's trial. Percentages of participants with first-cycle amenorrhea, hypomennorhea, and breakthrough bleeding were 7.5, 3.9, and 9.4 with Vestalin M and 2.0, 8.0, and 2.0 with Vestalin Uno. However, by the fifth cycle, the percentages with hypomennorhea were 25.8 and 12.2, respectively. The high gestagen level reduced the number of endometrial glands and the height of the lining epithelium and caused and excessive decidual reaction of the stroma, a reaction gradually involving the endometrium's compact basal layer, which has no involvement with the luteinization process of the secretory phase in normal women. The material shed included the necks of the endometrial glands responsible for the regeneration of the endometrium in subsequent cycles. When switching from a high to a low gestagen level, the endometrium regenerated and withdrawal bleeding lessened markedly in amount and duration. A few, less systematic, observations are reported for the women changing from 1 chemical composition to another.