Skin patch and vaginal ring versus combined oral contraceptives for contraception

The delivery of combination contraceptive steroids from a skin patch or vaginal ring offers potential advantages over those administered via the traditional oral route. The skin patch and vaginal ring could possibly require a lower dose due to increased bioavailability and improved user compliance.

The review's objective is to compare the contraceptive efficacy, cycle control, compliance, and safety of the contraceptive skin patch versus combination oral contraceptives and the contraceptive vaginal ring versus combination oral contraceptives.

We searched the computerized databases MEDLINE, Popline, Cochrane Controlled Trials Register, EMBASE, and LILACS for trials of the contraceptive patch or the contraceptive ring. We also searched the references of the publications identified for inclusion. We contacted the manufacturers of the skin patch and the contraceptive ring in an attempt to identify published or unpublished trials that we might have missed.

All randomized controlled trials in any language comparing the combination contraceptive skin patch with a combination oral contraceptive or the combination contraceptive vaginal ring with a combination oral contraceptive.

Titles and abstracts identified from the literature searches were assessed for potential inclusion. Data were abstracted by both the primary and second reviewers to ensure accuracy and were entered into RevMan 4.1. Peto odds ratios with 95% confidence intervals were calculated for all outcomes. Six- and 13-cycle Kaplan-Meier pregnancy rates were also entered into "Additional Tables." No sensitivity analyses were conducted since the eligible trials used different comparison oral contraceptives. The trials were critically appraised by examining the following factors: the study design; blinding; randomization method; group allocation concealment; exclusions after randomization; loss-to-follow-up; and early discontinuation.

We found three trials of the skin patch and no eligible randomized controlled trials of the combination contraceptive vaginal ring. The six-cycle and 13-cycle Kaplan-Meier cumulative probabilities of pregnancy showed that the combination contraceptive skin patch was similar to the control combination oral contraceptive in contraceptive efficacy. One trial found that patch users discontinued early from the trial more often than oral contraceptive users (OR 1.6; 95% CI, 1.3-2.0) but a second trial found no differences in discontinuation between the groups (OR 2.6; 95% CI, 1.0-6.7). Patch users had more self-reported cycles of compliance than oral contraceptive users; the odds ratio of compliance was 2.1 (95% CI, 1.8-2.3). Patch users were more likely to report breast discomfort than oral contraceptive users with an odds ratio of 3.1 (95% CI, 2.3-4.2). The remaining commonly reported adverse events did not differ by group assignment. One trial found that women assigned to use the patch were more likely to discontinue due to adverse events than those assigned to use the oral contraceptive (OR 2.3; 95% CI, 1.6-3.3), but a second trial found no difference (OR 2.8; 95% CI, 0.7-11.3). Few serious adverse events occurred that were considered possibly or likely related to the use of the patch or oral contraceptive.

The randomized controlled trials comparing a combination contraceptive skin patch to a combination oral contraceptive showed similar efficacy rates for the two methods. The patch group had better self-reported compliance than the oral contraceptive group. On the other hand, breast tenderness was more common among those randomized to the patch. The patch might lead to early discontinuation (overall and due to adverse events), but the trial results on this outcome were mixed. No conclusions can be drawn regarding the vaginal ring as no eligible trials were available.