While COCs containing 20 μg EE may be theoretically safer, this review did not focus on the rare events required to assess this hypothesis. Data from existing randomized controlled trials are inadequate to detect possible differences in contraceptive effectiveness. Low-dose estrogen COCs resulted in higher rates of bleeding pattern disruptions. However, most trials compared COCs containing different progestin types, and changes in bleeding patterns could be related to progestin type as well as estrogen dose. Higher follow-up rates are essential for meaningful interpretation of results.
Clinical comparison of two low-dose oral contraceptives, Minulet and Mercilon, in women over 30 years of age.
A comparative study of two low-dose oral contraceptives, gestodene (GES) 75 mcg/ethinyl oestradiol (EE) 30 mcg and desogestrel (DES) 150 mcg/EE 20 mcg, was conducted in women over 30 years of age. This randomised, open-label study was organised in Denmark, Italy, New Zealand and United Kingdom. A total of 505 women received GES/EE and 501 received DES/EE for 6 consecutive menstrual cycles. The two groups were comparable in terms of demographic and gynaecologic characteristics at baseline. However, the menstrual flow length was slightly longer in the GES/EE group before the start of the treatment. The mean age (+/- SD) was 35 +/- 4 years in the GES/EE group and 35 +/- 5 years in the DES/EE group. The subjects in the GES/EE group contributed data for a total of 2800 cycles and those in the DES/EE group, data for 2796 cycles. There were no pregnancies on medication with either preparation. The results showed that there were significantly more normal cycles in the GES/EE group for cycles 1 to 6. Irregular bleeding between withdrawal bleeds occurred in 10% of GES/EE and 18.5% of DES/EE cycles. Absence of all bleeding was reported in 29 (1%) and 63 (2%) cycles, respectively. The incidence of missed pills was low in both groups (11% of cycles). No significant differences were observed in cycle length or withdrawal bleeding episode length. Withdrawal bleeding mean intensity was statistically significantly greater with GES/EE. However, for both preparations, the mean intensity was close to light bleeding. No clinically significant differences were noted in weight, blood pressure, Papanicolaou smears or laboratory data. Sixty-eight (13.5%) subjects in the GES/EE group and 64 (12.8%) in the DES/EE group discontinued before the end of the study. Among them, 37 (7%) and 40 (8%) in the respective groups withdrew because of adverse reactions. There was no difference between groups in terms of primary reasons for withdrawal. The most frequently reported complaints that led to discontinuation in both groups were headache, nausea and metrorrhagia. Breast tenderness led to the discontinuation of 1 subject in the GES/EE group and 3 in the DES/EE group. These results show excellent cycle control, efficacy and very low rate of side effects with both GES/EE and DES/EE. These low-dose oral contraceptives could be well suited to healthy nonsmoking women requiring contraception up to the age of menopause.