The contraceptive vaginal ring compared with the pill in
RCT’s
F.J.M.E. Roumen
Atrium Medical Center, Heerlen, Netherlands
Objective The vaginal ring (CVR) and the pill (COC) are
both systemic forms of contraception with a comparable working mechanism and
nearly the same contraindications. The aim of this study was to compare
pharmacology, contraceptive efficacy, cycle control, and side effects between
both methods.
Design and methods All randomized controlled trials
comparing the CVR and the COC were analyzed, and the results of these studies
were reviewed.
Results Sixteen randomized controlled trials comparing
the CVR and the COC were identified. It was shown, that systemic exposure to
ethinyl estradiol (EE) with the CVR was only 50% of that for the COC,
accompanied by a lower degree of ovarian suppression. Contraceptive efficacy,
however, was excellent and comparable between both methods. Uterine
concentrations of EE and etonogestrel were not elevated with the CVR. Both
methods had no clinically relevant effect on carbohydrate metabolism, adrenal or
thyroid function. Cycle control achieved with the CVR was superior to that of
the COC. Compliance of both methods was high and comparable. Blood pressure and
body weight did not change significantly from baseline in either group. Adverse
events were comparable, but discontinuation for adverse events was higher in the
CVR groups due to local events. Whereas the incidence of breast tenderness,
headache, and nausea were comparable, a higher incidence of local and
ring-related events was seen in women using the CVR. Lactobacillus
colony-forming units were increased during CVR use and more women reported
vaginal wetness. Ring slippage was reported by one in ten women. Both
contraceptives were highly acceptable and resulted in a global improvement of
sexual function. Sexual fantasy was significantly increased in women and
partners using the CVR, whereas most of them never felt the ring during
intercourse.
Conclusions The contraceptive vaginal ring has the same
contraceptive efficacy as the pill with lower systemic EE exposure and superior
cycle control, but more local adverse events.