The skin patch and the vaginal (birth canal) ring are two methods of birth control. Both methods contain the hormones estrogen and progestin. The patch is a small, thin, adhesive square that is applied to the skin. The contraceptive vaginal ring is a flexible, lightweight device that is inserted into the vagina. Both methods release drugs like those in birth control pills. These methods could be used more consistently than pills because they do not require a daily dose. This review looked at how well the methods worked to prevent pregnancy, if they caused bleeding problems, if women used them as prescribed, and how safe they were.
Through February 2013, we did computer searches for randomized controlled trials of the skin patch or vaginal ring compared to pills for birth control. Pills included types with both estrogen and progestin. We wrote to researchers to find other trials.
We found 18 trials. Of six patch trials, five compared the marketed patch to birth control pills and one studied a patch being developed. Of 12 ring trials, 11 looked at the marketed ring and pills while one studied a ring being developed. The methods compared had similar pregnancy rates. Patch users reported using their method more consistently than the pill group did. Only half of the patch studies had data on pregnancy or whether the women used the method correctly. However, most of the ring studies had those data.
Patch users were more likely than pill users to drop out early from the trial. Ring users were not more likely to drop out early. Compared to pill users, users of the marketed patch had more breast discomfort, painful periods, nausea, and vomiting. Ring users had more vaginal irritation and discharge than pill users but less nausea, acne, irritability, depression, and emotional changes. Ring users often had fewer bleeding problems than pill users.
The quality of information was classed as low for the patch trials and moderate for the ring studies. Lower quality was due to not reporting how groups were assigned or not having good outcome measures. Other issues were high losses and taking assigned women out of the analysis. Studies of the patch and ring should provide more detail on whether women used the method correctly.
Effectiveness was not significantly different for the methods compared. Pregnancy data were available from half of the patch trials but two-thirds of ring trials. The patch could lead to more discontinuation than the COC. The patch group had better compliance than the COC group. Compliance data came from half of the patch studies and one-third of the ring trials. Patch users had more side effects than the COC group. Ring users generally had fewer adverse events than COC users but more vaginal irritation and discharge.
The quality of the evidence for this review was considered low for the patch and moderate for the ring. The main reasons for downgrading were lack of information on the randomization sequence generation or allocation concealment, the outcome assessment methods, high losses to follow up, and exclusions after randomization.
The delivery of combination contraceptive steroids from a transdermal contraceptive patch or a contraceptive vaginal ring offers potential advantages over the traditional oral route. The transdermal patch and vaginal ring could require a lower dose due to increased bioavailability and improved user compliance.
To compare the contraceptive effectiveness, cycle control, compliance (adherence), and safety of the contraceptive patch or the vaginal ring versus combination oral contraceptives (COCs).
Through February 2013, we searched MEDLINE, POPLINE, CENTRAL, LILACS, ClinicalTrials.gov, and ICTRP for trials of the contraceptive patch or the vaginal ring. Earlier searches also included EMBASE. For the initial review, we contacted known researchers and manufacturers to identify other trials.
We considered randomized controlled trials comparing a transdermal contraceptive patch or a contraceptive vaginal ring with a COC.
Data were abstracted by two authors and entered into RevMan. For dichotomous variables, the Peto odds ratio (OR) with 95% confidence intervals (CI) was calculated. For continuous variables, the mean difference was computed. We also assessed the quality of evidence for this review.
We found 18 trials that met our inclusion criteria. Of six patch studies, five examined the marketed patch containing norelgestromin plus ethinyl estradiol (EE); one studied a patch in development that contains levonorgestrel (LNG) plus EE. Of 12 vaginal ring trials, 11 examined the same marketing ring containing etonogestrel plus EE; one studied a ring being developed that contains nesterone plus EE.
Contraceptive effectiveness was not significantly different for the patch or ring versus the comparison COC. Compliance data were limited. Patch users showed better compliance than COC users in three trials. For the norelgestromin plus EE patch, ORs were 2.05 (95% CI 1.83 to 2.29) and 2.76 (95% CI 2.35 to 3.24). In the levonorgestrel plus EE patch report, patch users were less likely to have missed days of therapy (OR 0.36; 95% CI 0.25 to 0.51). Of four vaginal ring trials, one found ring users had more noncompliance (OR 3.99; 95% CI 1.87 to 8.52), while another showed more compliance with the regimen (OR 1.67; 95% CI 1.04 to 2.68).
More patch users discontinued early than COC users. ORs from two meta-analyses were 1.59 (95% CI 1.26 to 2.00) and 1.56 (95% CI 1.18 to 2.06) and another trial showed OR 2.57 (95% CI 0.99 to 6.64). Patch users also had more discontinuation due to adverse events than COC users. Users of the norelgestromin-containing patch reported more breast discomfort, dysmenorrhea, nausea, and vomiting. In the levonorgestrel-containing patch trial, patch users reported less vomiting, headaches, and fatigue.
Of 11 ring trials with discontinuation data, two showed the ring group discontinued less than the COC group: OR 0.32 (95% CI 0.16 to 0.66) and OR 0.52 (95% CI 0.31 to 0.88). Ring users were less likely to discontinue due to adverse events in one study (OR 0.32; 95% CI 0.15 to 0.70). Compared to the COC users, ring users had more vaginitis and leukorrhea but less vaginal dryness. Ring users also reported less nausea, acne, irritability, depression, and emotional lability than COC users.
For cycle control, only one trial study showed a significant difference. Women in the patch group were less likely to have breakthrough bleeding and spotting. Seven ring studies had bleeding data; four trials showed the ring group generally had better cycle control than the COC group.