Transdermal and Vaginal Ring Hormonal Contraceptives
A quick-start protocol, similar to that used for oral contraceptives (OCs), can be used for transdermal (patch) and vaginal ring contraceptives. If either contraceptive method is started at any time other than the first 5 days of menses, a backup contraceptive method should be used concurrently for 7 days.
A 20-cm2 transdermal patch delivers 150 mcg of the progestin norelgestromin (the active metabolite of norgestimate) and 20 mcg of ethinyl estradiol daily into the systemic circulation for 7 days. After 1 wk, the patch is removed, and a new patch is applied to a different area of the skin. After 3 patches are used, no patch is used for the 4th wk to allow for withdrawal bleeding.
Hormone blood levels of estrogen and progestin are much more constant with the patch than with OCs. Overall, contraceptive efficacy, incidence of bleeding, and adverse effects with the patch are similar to those with OCs, but patient adherence may be better with the patch because it is applied weekly rather than taken daily. The patch may be less effective in obese women who weigh > 90 kg.
Women should be advised to use a backup contraceptive method concurrently for 7 days if > 2 days have elapsed since a new patch was to be applied.
In the US, only one type of vaginal ring is currently available. This vaginal ring is flexible, soft, and transparent; it comes in only one size and is 58 mm in diameter and 4 mm thick. Each ring releases 15 mcg of ethinyl estradiol (estrogen) and 120 mcg of etonogestrel (progestin) daily. These hormones are absorbed through the vaginal epithelium. When a vaginal ring is used, hormone blood levels are relatively constant.
Women insert and remove the ring themselves; no fitting by a physician is required. The ring is typically left in place for 3 wk, then removed for 1 wk to allow for withdrawal bleeding. However, each ring contains enough hormone to effectively inhibit ovulation for up to 5 wk. Thus, the ring may be used continuously and replaced with a new ring every 5 wk. With continuous use, breakthrough bleeding is more common, and the possibility of this adverse effect should be explained to women who are considering continuous use.
Contraceptive efficacy and adverse effects with vaginal rings are similar to those of OCs, but adherence may be better with rings because they are inserted monthly rather than taken daily.
Women may wish to remove the vaginal ring at times other than the week for withdrawal bleeding. However, if the ring is removed for > 3 h, women should be advised to use a backup contraceptive method concurrently for 7 days.