During oral treatment with 3 mg micronized
17 beta-estradiol and 0.150 mg
desogestrel for 21 days followed by 0.030 mg (A)
desogestrel (15 women) or placebo (B) (14 women) for 7 days, ovarian function,
bleeding pattern and
estradiol levels were evaluated. The study was performed in a group-comparative, double-blind fashion. During a pre-treatment control cycle, using ultrasound scan, follicular diameter was measured on cycle days 10-16 and endometrial thickness on one of cycle days 22-26.
Estradiol was measured at the time of ultrasound scan and
progesterone three times in the luteal phase. During three treatment cycles, follicular diameter and endometrial thickness were monitored three times weekly and at the same time,
estradiol and
progesterone were measured. Treatment resulted in
anovulation in all women. Maximum and mean
estradiol levels were approximately 900 pmol/l and 550 pmol/l during treatment, respectively, and approximately 200 pmol/l during the
estradiol-free weeks in both groups. Ten women showed ovarian activity (follicle size > or = 15 mm) during treatment, seven in group A and three in group B. Endometrial thickness decreased approximately 3 mm during treatment in both groups. The incidence of
breakthrough bleeding and
spotting was higher in group A when compared to group B. The study indicates that the combination of 3.0 mg micronized
estradiol and 0.150 mg
desogestrel is an effective and safe
contraceptive, offering an acceptable cycle control. The addition of a low dose of
desogestrel during the pill-free period did not further suppress ovarian activity nor improve the
bleeding pattern. The results of this study should be interpreted with great care, since the number of women studied is relatively small.