Review: contraceptive patch and vaginal ring are as effective as oral contraceptives
Dr L Lopez, Family Health International, Research Triangle Park, NC, USA;
How do the contraceptive skin patch and vaginal ring compare with combination oral contraceptives (COCs) for contraceptive effectiveness, cycle control, and side effects?
Studies selected compared the contraceptive skin patch (norelgestromin, 150 µg, plus ethinyl estradiol, 20 µg daily; patch changed weekly for 3 wks, then 1 patch-free wk) or contraceptive vaginal ring (etonogestrel, 120 µg, plus ethinyl estradiol, 15 µg daily, kept in place for 3 wks, then 1 ring-free wk; or nestorone, 150 µg, plus ethinyl estradiol, 15 µg daily, kept in place for 1 y) with any COC for ⩾3 menstrual cycles in women of reproductive age (18–45 y) with regular menstrual cycles. Outcomes were pregnancy, cycle control, compliance, discontinuation, and side effects.
Medline, POPLINE, Cochrane Central Register of Controlled Trials, EMBASE/Excerpta Medica, and LILACS (to Jan 2007); and references were searched for randomised controlled trials (RCTs). Researchers and patch or ring manufacturers were consulted. 3 RCTs of the patch (n = 3622) and 8 RCTs of the vaginal ring (n = 2848) met the selection criteria. 7 trials reported adequate allocation concealment, 2 trials had <10% loss to follow-up, and no trials were blinded.
Meta-analysis was not done for most outcomes because of differences in COCs used in the control groups. The table shows the results.
The contraceptive patch and vaginal ring have contraceptive effectiveness similar to that of combination oral contraceptives (COCs) and do not increase bleeding problems. Compliance is better with the patch than with COCs, but side effects and discontinuation are more likely. The vaginal ring had compliance and discontinuation rates similar to COCs, with no increase in side effects except for vaginitis and leucorrhoea.
Lopez LM, Grimes DA, Gallo MF, et al. Skin patch and vaginal ring versus combined oral contraceptives for contraception. Cochrane Database Syst Rev 2008;(1):CD003552.
Clinical impact ratings: Family/general practice 6/7; Sexual health 6/7; Women’s health 5/7
Source of funding: National Institute of Child Health and Human Development and US Agency for International Development.
Use of COCs for birth control and menstrual irregularities is well established in women’s health care. Many studies have outlined the benefits and limitations of COCs. Side effects and women’s fears over long-term use of COCs have led to a search for alternative hormonal therapies.
The review by Lopez et al focused on the effectiveness of skin patches and vaginal rings and provides some interesting findings on the relative efficacy of these alternative routes of hormone administration compared with COCs. However, little information was given about the settings of the trials or the profiles of the women (except for age). Factors such as ethnicity and menstrual patterns have been shown to affect successful use of hormone therapy; without this information, it is difficult to assess the generalisability of the results.
The results of the review by Lopez et al become more clinically important given that, unlike COCs, the effectiveness of the Evra patch is not appreciably diminished by use of tetracycline (commonly prescribed after pregnancy termination to reduce infection risk).1 However, a note of caution is required: current evidence is conflicting as to whether risk of thrombosis is higher with daily use of the hormonal patch compared with the usual oral administration route.2 3
The review provides some insight into the relative success of using the skin patch or vaginal ring as alternative routes of hormonal contraception administration. This information will be useful to nurses in gynaecology, family planning, and abortion clinics when providing birth control counselling to women, particularly those with concerns about side effects, reduced efficacy, or long-term use of oral contraceptives.