Depo-Provera is a reversible, long-lasting contraceptive injected into the muscles of the upper arm or buttocks and slowly released into the body over a period of three months. It contains medroxyprogesterone acetate, a synthetic form of progesterone similar to the progesterone your body produces during the second half of your menstrual cycle. Depo-Provera prevents the eggs in your ovaries from maturing and thus inhibits ovulation. It keeps the lining of the uterus thin (unreceptive to a fertilized egg) and the cervical mucus thick (so sperm cannot penetrate it).

How effective is Depo-Provera?

Depo-Provera is more than 99 percent effective, both in theory and in practice when used as directed. It is easy to be consistent and conscientious, since you only have to remember to get a shot four times yearly.

Are there reasons for not taking Depo-Provera?

You should not take Depo-Provera if there is even a remote chance you might be pregnant. Tell your doctor if you have had unexplained vaginal bleeding, breast cancer, an abnormal mammogram, stroke, blood clots, or liver disease. Also mention any family or personal history of kidney disease, high blood pressure, migraine headaches, asthma, diabetes, epilepsy, or depression.

Nursing mothers can use Depo-Provera. It does appear in the breast milk, but does not affect its quantity or quality. Long-term studies that followed children through adolescence have shown no adverse effects on babies nursed by mothers who took Depo-Provera. In fact, sometimes the first shot is given in the hospital before the mother goes home.

At what time of the month should you get your first shot?

You should get your first shot within five days after a regular menstrual period begins, to be sure you are not already pregnant. Before you get your first shot, your doctor will give you a physical exam; at this time bring up any conditions that might make Depo-Provera a poor choice for you. Most women say that the shot is not painful, though the site of the injection may be sore for a day or so.

If you get your first injection during the first five days after you have begun a normal menstrual period, you are protected from pregnancy immediately: you have not yet ovulated that month, and the hormone will have time to block ovulation before it happens.

What if you for get your three-month injection or cant come at the scheduled time?

It is safe to have your injection a week or so early if your three-month date is not convenient, but if you wait longer than three months, you must use another reliable kind of birth control (condoms or spermicides) until you get your injection. Try scheduling your next injection when you get your present one and mark the date on your calendar.

Does Depo-Provera protect against STDs?

Because it contains progesterone, Depo-Provera does help protect you from pelvic inflammatory disease, that is, from the spread of disease upward into your uterus and fallopian tubes. But it does not protect you from infection in the first place. You can get human immunodeficiency virus, chlamydia, gonorrhea, or any other sexually transmitted disease while you are on Depo-Provera.

Does Depo-Provera increase the risk of breast cancer? Of osteoporosis?

Depo-Provera has been available throughout the world for more than thirty years and has been used by more than 9 million women. It was introduced into the United States twenty-five years ago but withdrawn from the market when studies showed that beagle dogs given massive doses of Depo-Provera had an increase in breast cancer. However, beagles were chosen as test animals because of their susceptibility to cancer, and long-term studies on women taking normal doses of Depo-Provera have not shown significantly increased risk. A study undertaken by the World Health Organization in Switzerland reviewed previous research and concluded that Depo-Provera does not increase the risk of breast cancer.

Since Depo-Provera suppresses the natural production of estrogen (which protects against osteoporosis), theoretically it could increase the risk of osteoporosis, a disease in which bones lose their calcium and become weak and porous. One study showed that women who used Depo-Provera longer than five years did show decreased bone density. Other research has shown that bone loss on Depo-Provera is only a problem for smokers, who have increased risk anyhow. Women who have several risk factors for osteoporosis (slender build, fair skin, low calcium intake, lack of weight-bearing exercise) might discuss the matter with their caregivers before deciding on Depo-Provera.

How does Depo-Provera affect menstrual periods?

Most women who use Depo-Provera notice some change in their normal menstrual pattern, because Depo-Provera prevents ovulation and the usual cyclical buildup and shedding of the uterine lining. This disruption can be in the form of breakthrough bleeding, usually just spotting or staining. Or the disruption can mean no periods at all, or periods that are regular but lighter than usual. The longer you use Depo-Provera, the less likely you are to have irregular bleeding or any menstrual periods at all. After one year of using Depo-Provera, 57 percent of women stop having menstrual periods; after two years, the figure is 68 percent.

Unfortunately, some women have long-term irregular bleeding, which means that they can never be sure when they are going to start bleeding. Some women have light bleeding every day for three months; these women usually stop using Depo-Provera because of the nuisance and inconvenience. If you do have heavy or continuous bleeding or a persistent abnormal pattern of bleeding, let your caregiver know so that disease can be ruled out.

What are the side effects of Depo-Provera?

Depo-Provera can cause irritability. If it does, you may remain irritable for three months until the effects of the shot wear off — which can be unpleasant for you and those around you. Most women do not have these negative feelings, and in fact Depo-Provera is sometimes used as a treatment for premenstrual syndrome, which has increased irritability as one of its symptoms. Occasionally women become depressed while taking Depo-Provera.

One of Depo-Provera’s drawbacks is that it makes some women feel bloated and causes them to gain weight. Studies by the manufacturer show that women who do gain weight on Depo-Provera put on slightly more than five pounds during the first year and keep on gaining. After six years the women who put on weight gained an average of sixteen and a half pounds. This only happens to a few women, but it is distressing for those who do not want to gain weight.

In my medical practice, I have found weight gain on birth control pills to be different from that on Depo-Provera. Women who complain that oral contraceptives have made them put on an extra ten pounds sometimes have gained the weight simply because they have eaten too much. When they change contraceptives, the weight fails to disappear.

What does Depo-Provera cost?

The four yearly shots cost in the range of sixty to seventy-five dollars apiece, in addition to the cost of the office appointments, so the annual total is about the same as for birth control pills. Currently many health maintenance organizations do not cover contraceptive protection, so you may have to pay these expenses out of pocket.

Does using Depo-Provera make it difficult to get pregnant later?

Depo-Provera does not interfere with fertility once the effects of the most recent shot have worn off. Sixty-eight percent of women who become pregnant after quitting Depo-Provera do so within the first year; 93 percent, within a year and a half. The length of time you have been using Depo-Provera bears no relation to how long it takes to get pregnant when you discontinue usage.

What are its advantages and disadvantages?

Depo-Provera is convenient and effective. You do not have to think about it. If you have had heavy, painful periods, it may offer relief. It may help with premenstrual syndrome. It gives some protection against pelvic inflammatory disease, and it may decrease the risk of endometrial cancer.

On the negative side, it is long-lasting, so if you decide you would like to become pregnant, you might have to wait for your last shot to wear off. It does not protect against sexually transmitted diseases. It can have unpleasant side effects, including weight gain.

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