There are many forms of birth control to prevent unplanned pregnancy. Birth control injections are one way to introduce the birth control hormone into the system. These are known as Depo-Provera shots. Women take them in the doctor’s office every 3 months and they can prevent pregnancy from happening for 3 months at a time.

Around 22% of women in the United States have at least tried birth control shots. It is estimated that 6 out of 100 women who use Depo-Provera became pregnant while using them (some don’t always use the birth control shot as directed). Even though, it is still a popular choice for birth control due to its convenience. Read further to learn more about birth control injections.

What Are Birth Control Injections?

Birth control injections are similar hormones used in birth control pills injected every three months to prevent pregnancy. Many women who take birth control shots have found them to have several benefits over and above just birth control, including:

• No pills to remember
• Taken only once every 3 months
• Very effective method of birth control
• Fewer, lighter or no periods
• Does not contain Estrogen and no cardiac risks (Blood clots, heart attack, or stroke)
• Fewer drug interactions i.e. antibiotics, seizure medications, and alcohol
• Reduces risk for reproductive cancers by 80 percent
• Reduction in symptoms of reproductive issues (endometriosis, uterine fibroids, and ovarian cysts)
• Less cases of anemia associated with heavy periods
• Women with epilepsy have less seizures
• Women with sickle cell anemia have less reported “sickle cell crisis”

Many of these benefits are related to less heavy periods, less bleeding, and lower hormonal shifts over the three month period that the Depo-Provera is in effect.

How Birth Control Injections Work

Birth control injections are made of progestogen only and contain no estrogen. It is given in high doses every three months to prevent the following:

• Keeps the eggs in the ovaries from becoming mature
• Prevents ovulation
• Keeps estrogen levels low to prevent the uterine lining from building up
• Changes the cervical mucus to make it unfavorable for sperm
• May prevent a fertilized egg from implanting (In theory, but not proven yet)

There are some women who use birth control injections for endometriosis. It has proven to be very beneficial in reducing the amount of uterine tissue build-up outside the uterus and reducing associated pain with the condition.

The information above shows the many benefits of birth control shots. It must be understood that for the injections to be most effective, they must be taken on-time and used correctly.

How Are Birth Control Injections Applied?

Note: Birth control injections are most effective when the following instructions are very carefully followed.

If you want to start taking shots for birth control, make an appointment with your doctor or nurse practitioner. They will do a physical exam, ask the date of your last menstrual period and do lab work to make sure you are not pregnant.

If you just had a baby the doctor will only give the injection in the first 5 days after the baby is born. Breastfeeding mothers will need to wait until the baby is six weeks old to ensure adequate milk supply is established.

If the doctor gives you the all clear, you will receive your first injection and be given information on how to maintain this birth control method including:

• Take injections on time. You will need to return to your doctor’s office every 3 months and no longer than 13 weeks for follow-up injections. If you are late getting your shot, your doctor may want to do a pregnancy test first.
• Changing over from birth control pills. If you are choosing to use birth control injections and stopping birth control pills, the doctor will have you finish your last pack of pills and your shot will be given the day after the last pill was taken. This is to prevent “breakthrough ovulation.”
• Take the shot in the buttocks. Depo-Provera can be taken in either the buttocks or the upper arm. Women have found the injection far less painful when taken in the buttocks.
• Get yearly check-ups. Your doctor will advise you to get yearly check-ups while on birth control injections. You will need to have your blood pressure, cholesterol, and overall general health checked each year to make sure your health is stable enough to continue to take the shots. While the cardiac risks are lower, as you age the risks do increase.
• Use another form of protection for STDs. Like birth control pills, foams, and the diaphragm, birth control shots do not protect from sexually transmitted diseases. You will need to use a condom if you have multiple or new sex partners.

How Well Do Birth Control Injections Work?

Birth control injections range from 94 percent to 99.8 percent effective when used as a birth control method. About 1 in 100 women who take birth control shots become pregnant every year. These numbers apply to women who take the shots on time and start the injections at the right time during their cycle.

Side-Effects of Birth Control Injections

There are actually very few side-effects with birth control injections, including:

• Irregular periods or absence of periods during the cycle
• May take up to 7 days to be effective if given late in the cycle
• Does not protect against sexually transmitted disease
• Takes up to 10 months to become fertile after you stop using it
• Decreased libido
• Weight gain
• Anxiety/Nervousness
• Headaches
• Nausea

Most women who use birth control shots tolerate them very well. Side-effects tend to diminish after a few cycles of shots.

Health Concerns

If you have any of the following health conditions, you will need to discuss using birth control injections with your doctor to decide if it is safe:

• Cardiac disease or blood clotting disorders/History of blood clots
• High blood pressure
• Diabetes more than 20 years
• Breast cancer that is sensitive to hormones
• Liver disease or active hepatitis
• Unexplained vaginal bleeding
• Migraines during use
• If you are pregnant
• Women and adolescents who use birth control shots should talk to their doctor about taking calcium with the shots because it can lower the density of bones. Women with osteoporosis may want to take this into consideration when choosing Depo-Provera.
• If you are taking aminoglutethamide to treat Cushing’s syndrome, do not take birth control injections