What is it?
Depo-Provera is an injection (a shot) that protects against pregnancy for three months (up to 15 weeks).
How does it work?
The injection contains a progestin (a synthetic progesterone) called medroxyprogesterone acetate. It prevents pregnancy by:
- Preventing ovulation (the release of eggs from the ovary)
- Thickening cervical mucus which prevents sperm from entering the uterus.
- Changing the lining of the uterus, making it less likely for implantation (or less likely for pregnancy) to occur.
Depo-Provera does not contain estrogen.
How is it given?
Depo-Provera is injected in to the muscle of your buttock. The injection will prevent pregnancy for three months and the birth control effects begin as soon as you have your first shot. The injection should be repeated every three months (11-15 weeks) as long as birth control protection is wanted. If an injection is late or missed, pregnancy can occur.
How effective is Depo-Provera?
Depo-Provera is highly effective. It works as well as sterilization (with less than one pregnancy per 100 users, 99.7% effective). It is more effective than the birth control pill because it is not dependent upon correct daily usage. (Some women get pregnant taking birth control pills if they take pills incorrectly or miss pills.)
What are the side effects?
The most common side effect is a change in the menstrual cycle. Irregular or unpredictable bleeding or spotting often occur. Bleeding may be lighter or heavier than usual, spotting between periods may occur or women may have no periods. After about one year many women will stop having periods. The lack of periods does not mean that you are pregnant if you have received injections regularly every three months.
Depo-Provera is not a good choice if you want to be pregnant in the next year or two. Why? Because it can take 12-18 months to become pregnant after you stop taking Depo-Provera as a contraceptive. The length of time you use Depo-Provera has no effect on how long it takes you to become pregnant. If you do not wish to become pregnant after stopping Depo-Provera then you should start another form of birth control immediately.
Other side effects reported less often than changes in menstrual cycle include:
- Weight gain (average 5 lbs. in 1st year)
- Stomach pain or cramps
- Weakness or fatigue
- Decreased sex drive
Most of the side effects listed decrease over time when using Depo-Provera. But because Depo-Provera is long lasting, any side effects are likely to continue over a period of time, until the progestin hormone has worn off. It is important to discuss any side effects experienced with this method or any other method with a health care provider.
Depo-Provera does not provide protection against sexually transmitted infections. Use latex condoms for increased protection against the transmission of STIs including HIV.
Who can use Depo-Provera?
Depo-Provera may be used by most women who want a method that is highly effective and long lasting. Depo-Provera is also a good choice for a woman who does not want to take a pill every day or use a method right before intercourse. It is a good method for women who cannot take estrogens.
Depo-Provera should not be used if:
- You think you might be pregnant
- You have abnormal vaginal bleeding without a known reason
- You have had cancer of the breast or reproductive organs
- You have had a stroke
- You have or had blood clots (phlebitis) in your legs
- You have problems with your liver or liver disease
- You are allergic to Depo-Provera
(medroxyprogesterone acetate or any of its other ingredients)
Depo-Provera and bone density:
Women using Depo-Provera may experience bone loss resulting in decreased bone density. We don’t know whether this increases risk of osteoporosis later in life, but we do know that Depo-Provera users do not have more bone fractures than non-users. Bone density improves after discontinuation of Depo-Provera and probably returns to normal.
An FDA warning states that Depo-Provera should be used as a long-term birth control method (longer than 2 years) only if other birth control methods are inadequate; and women who continue to use Depo-Provera past the two-year mark should have a bone mineral density test. However, the World Health Organization recommends that women 18-45 years old can use Depo-Provera without restrictions and without need for bone mineral testing.
It is important that you get adequate calcium in your diet and/or supplements totaling 1200 mg of calcium and 400 mg vitamin D daily. It is also important to avoid smoking, get regular weight-bearing exercise such as walking, running, and weight lifting, and limit intake of carbonated and caffeinated beverages.
What is the Health Center procedure for Depo injections?
First Injection: an appointment is made with one of the practitioners to review your history and discuss the pros and cons of the Depo-Provera method. You can then receive your first injection anytime if there is no possibility of pregnancy.
Follow up Injections: make an appointment with your practitioner 11-15 weeks after your first injection. Your weight and blood pressure will be taken and response to the contraceptive will be reviewed. You will then be given your injection.