Combined estrogen-progestin contraceptives can be administered through a transdermal or vaginal route and are available as skin patches and vaginal rings.
The efficacy of the estrogen-progestin patches and rings are the same as oral contraceptives (OCs); the pregnancy rate after 1 year is 0.3% with perfect use and about 9% with typical (ie, inconsistent) use. Adherence is typically better with a patch or ring than with OCs, because dosing is every 1 to 3 weeks rather than daily.
A quick-start protocol, similar to that used for OCs, can be used for patches and rings. 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.
Breakthrough bleeding is uncommon when transdermal or ring contraception is used. If breakthrough bleeding occurs, it typically decreases within 2 to 6 months of use.
Contraindications are the sames as for OCs.
Transdermal contraceptives
There are 2 contraceptive patches available in the United States. The medications, approximate dose released daily for 7 days, and size of each are:
Ethinyl estradiol 35 mcg and norelgestromin (the active metabolite of norgestimate) 150 mcg, 14 cm2
Levonorgestrel 120 mcg and ethinyl estradiol 30 mcg and , 28 cm2
After 1 week, 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 week to allow for withdrawal bleeding.
Hormone blood levels of estrogen and progestin are much more constant with the skin patches than with oral contraceptives (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 women who weigh > 90 kg or have a body mass index (BMI) ≥ 30.
Patients 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.
Vaginal ring contraceptives
Vaginal rings are flexible, soft, and transparent. Two types of rings are available:
etonogestrel (progestin) and 15 mcg of ethinyl estradiol (estrogen) a day; a new ring must be used each month
ethinyl estradiol (estrogen) a day; a new ring is used only once a year
Both types of rings are typically left in place for 3 weeks, then removed for 1 week to allow for withdrawal bleeding. The year-long ring is removed, left out for 1 week, and then the same ring is reinserted.
Adverse effects with vaginal rings are similar to those of OCs, but patient adherence may be better with a vaginal ring because it is inserted monthly rather than taken daily.
Women may wish to remove the vaginal ring at times other than after 3 weeks. However, if the ring is removed for > 3 hours, women should be advised to use a backup contraceptive method concurrently for 7 days.
Women insert and remove the ring themselves; no fitting by a clinician is required.
The hormones released by vaginal rings are absorbed through the vaginal epithelium. When a vaginal ring is used, hormone blood levels are relatively constant.
