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. Little is known about how these methods compare to birth control pills. This review looked at how well the methods worked to prevent pregnancy, how safe they were, if they caused bleeding problems, and if women used them as prescribed.
We did a computer search 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 15 trials; 5 compared the patch to birth control pills and 10 looked at the ring and pills. The methods compared had similar pregnancy rates. 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, patch users had more breast discomfort, painful periods, nausea, and vomiting. Ring users had less nausea, acne, irritability, and depression than pill users. Ring users often had fewer bleeding problems but more vaginal irritation and discharge. Patch users reported using their method more consistently than the pill group did.
Compared to pill users, the patch group had more side effects while ring group had fewer. The patch might lead to stopping the birth control method early. High losses to follow up can lower the value of the results. Studies of the skin patch and vaginal ring should provide more detail on whether women used the method correctly.