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Birth control - slow release methods

Certain birth control methods contain man-made forms of hormones that are normally made in a woman's ovaries. These hormones are called estrogen and progestin.

  • Both estrogen and progestin prevent a woman's ovaries from releasing an egg during her menstrual cycle (called ovulation). They do this by changing the levels of the natural hormones the body makes.
  • Progestins also help prevent sperm from entering the uterus by making the mucus around a woman's cervix thick and sticky.

Birth control pills are one way of receiving these hormones. However, you must remember to take the pills every day.

Other methods to prevent pregnancy use the same hormones, but these hormones are released slowly over time.

Alternative Names

Contraception - hormonal methods; Progestin implants; Progestin injections; Skin patch; Vaginal ring



A progestin implant is a small rod that is implanted under the skin, usually on the upper arm. The rod releases a small amount of the hormone progestin into the bloodstream.

It takes about a minute to insert the rod, which is done using a numbing medicine in a doctor's office. The rod can stay in place for 3 years, but it can be removed at any time. Removal usually takes only a few minutes.

After the implant has been inserted:

  • You may have some bruising around the site for a week or more.
  • You should be protected from getting pregnant within 1 week.
  • You can use these implants while breastfeeding.

Progestin implants work better than birth control pills to prevent pregnancy. In any one year, only 1 out of every 100 women who use these implants is likely to get pregnant.

Your regular menstrual cycles should return within 3 - 4 weeks after these implants are removed.


Injections or shots that contain the hormone progestin also work to prevent pregnancy. A single shot works for up to 90 days. These injections are given into the muscles of the upper arm or buttocks.

Side effects that may occur include:

  • Changes in menstrual cycles or extra bleeding or spotting. Around half of women who use these injections have no menstrual cycles
  • Breast tenderness, weight gain, headaches, or depression

Progestin injections work better than birth control pills to prevent pregnancy. In any one year, only 1 out of every 100 women who use progestin injections is likely to get pregnant.

Sometimes the effects of these hormone shots last longer than 90 days. If you are planning to become pregnant in the near future, you might want to consider a different birth control method.


The skin patch is placed on your shoulder, buttocks, or another area of your body.

  • A new patch is applied once a week for 3 weeks. Then you go 1 week without a patch.
  • Estrogen levels are higher with the patch than with birth control pills or the vaginal ring. Because of this, there may be an increased risk of blood clots in the legs or lungs with this method. The FDA has issued a warning about the patch and the higher risk of a blood clot traveling to a lung.

The patch slowly releases both estrogen and progestin into your blood. Your health care provider will prescribe this method for you.

The patch works better than birth control pills to prevent pregnancy. In any one year, only 1 out of every 100 women who use the patch is likely to get pregnant.

The skin patch contains estrogen. Along with the higher risk of blood clots, there is a rare risk of high blood pressure, heart attack, and stroke. Smoking increases these risks even more.


The vaginal ring is a flexible ring about 2 inches wide that is placed into the vagina. It releases the hormones progestin and estrogen.

  • Your health care provider will prescribe this method, but you will insert the ring yourself.
  • It will stay in the vagina for 3 weeks. At the end of the third week, you will take the ring out for 1 week. Do not remove the ring until the end of the 3 weeks.

Side effects with the ring may include:

  • Nausea and breast tenderness, which are less severe than with birth control pills or patches
  • Vaginal discharge or vaginitis
  • Breakthrough bleeding and spotting (may occur more often than with birth control pills)

The vaginal ring contains estrogen. As a result, there is a rare risk of high blood pressure, blood clots, heart attack, and stroke. Smoking increases these risks even more.

The vaginal ring slowly releases both estrogen and progestin into your blood.

The vaginal ring works better than birth control pills to prevent pregnancy. In any one year, only 1 out of every 100 women who use the vaginal ring is likely to get pregnant.


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Hickey M, Kauntz AM. In: Kronenberg HM, Melmed S, Polonsky KS, Larsen PR, eds. Williams Textbook of Endocrinology. 12th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 18.

Lopez LM, Grimes DA, Gallo MF, Schulz KF. Skin patch and vaginal ring versus combined oral contraceptives for contraception. Cochrane Database Syst Rev. 2008;(1):CD003552.

March LS, Lakkegaard E, Andreasen AH, Krager-Kjaer L, Lidegaard O. Hormone therapy and ovarian cancer. JAMA. 2009;302:298-305.

Pickle S, Wu J, Burbank-Scmitt E. Prevention of unintended pregnancy: A focus on long-acting reversible contraception. Prim Care Clin in Office Prac. 2014;41:239-260.

Spencer AL, Bonnema R, McNamara MC. Helping women choose appropriate hormonal contraception: update on risks, benefits, and indications. Am J Med. 2009;122:497-506.

Updated: 6/11/2014

Cynthia D. White, MD, Fellow American College of Obstetricians and Gynecologists, Group Health Cooperative, Bellevue, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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