Injections and Combination Injections

Injections

An injection of synthetic hormone medroxyprogesterone acetate (DMPA, Depo-Provera) can be given every 3 months to stop ovulation. The injection is given at a doctor's office. After injection, the medication is active within 24 hours and lasts for 3 months. It prevents the ovaries from releasing eggs.
 

• How effective: DMPA is an extremely effective contraceptive option. Most other medications or a woman's weight do not change its effectiveness. Within the first year of use, the failure rate is 0.3%. 
  
  
• Advantages: DMPA does not produce the serious side effects that estrogen does, such as blood clotting. It lowers the risk for certain endometrial and ovarian cancers. Irregular periods may become regular.
  
  
• Disadvantages: Some women may not have a period within the first year. Irregular bleeding can be treated by giving the next dose earlier or by temporarily adding a low-dose estrogen. Because DMPA lasts in the body for several months in women who have used it on a long-term basis, it can delay the return to fertility. About 70% of former users desiring pregnancy conceive within 12 months, and 90% of former users conceive within 24 months. Other side effects, such as weight gain, depression, and menstrual irregularities, may continue for as long as 1 year after the last injection. Recent studies suggest a possible link between DMPA and bone density loss. Results are conflicting and limited. This method does not protect against STDs.

One of the newest developments in contraception is a combined monthly injection (medroxyprogesterone acetate [progesterone] and estradiol cypionate [estrogen], brand name Lunelle). It recently received FDA approval in the United States. The injections stop ovulation (like birth control pills do). They thicken cervical mucus to prevent sperm from traveling up the Fallopian tubes to fertilize an egg, and thin the uterine lining to prevent an egg from implanting.

Women who want to become pregnant may stop using Lunelle at any time. Some women have an immediate return to fertility. Others may have to wait 60-90 days for normal menstrual cycles.

• How effective: When used correctly, Lunelle is 99.8% effective. One-year failure rates of less than 1% have been reported in clinical trials. In one US study of 782 women, no pregnancies were reported after one year of use. 
  
  
• Advantages: A woman can regain fertility after 2-3 months after the last injection. Few users of Lunelle experience problem periods or no periods. Lunelle can protect the uterus from cancer and endometriosis and reduce the likelihood of ovarian cysts and tumors. 
  
  
• Disadvantages: Disadvantages include irregular blood spotting, weight gain, headache, mild depression or mood changes, and possible decrease in sexual desire. You are required to see your health care provider each month for the injections and may have to fill the prescription at the pharmacy and then take the medication with you to the provider for the injection. Injections are given every 28-30 days and no later than 33 days after the last injection. Timing is determined by the number of days, not your menstrual period. Some women may not have a period but should have the injection on schedule. In contrast to other hormonal contraceptive methods, due to its novelty, associated cancer risk is not known. More extensive worldwide use and additional studies may demonstrate the risk, if any, on cancer of the reproductive tract. Some women may experience changes in vision, especially for contact lens wearers. There is a higher risk of gallbladder disease. Any woman with a history of blood clots, stroke, heart disease, breast cancer, unexplained vaginal bleeding, and high blood pressure should avoid Lunelle. Women older than 35 years who smoke should not have these injections. This method does not protect against STDs.

Unfortunately, the combination injectable contraceptive is no longer available in the United States, although it is popular in Central America and South America and other parts of the world.