OVARIAN ACTIVITY SUPPRESSION BY 2 DIFFERENT LOW-DOSE TRIPHASIC ORAL-CONTRACEPTIVES

In an open, randomized study in an outpatient clinic of a large teachi ng hospital, thirty-one female volunteers with regular cycles and esta blished ovulation by ultrasonography were given one of two triphasic o ral contraceptives containing ethinylestradiol combined with levonorge strel or desogestrel during six cycles og treatment. The main outcome measures were transvaginal ultrasonography and serum E(2) and P measur ements in pill cycles 1, 3 and 6. No ovarian activity was found in 10 subjects. Among the remaining 21 women who showed ovarian activity, mo st follicle-like structures developed in the pill-free week and decrea sed in size or disappeared in the first pill week. One women taking tr iphasic desogestrel had evidence of a luteinized unruptured follicle a nd one women taking triphasic levonorgestrel had a possible ovulation. The latter women also showed symptoms of lower abdominal pain. A stat istically significant difference in ovarian activity between the two o ral contraceptives could not be established. The two triphasic oral co ntraceptives suppressed ovarian activity to the same degree. A trend w as seen towards increasing ovarian activity with duration of use in bo th treatment groups.