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.