Out of all the contraceptives available, Depo-Provera is one of the most common. Often short named as depo, it is taken in the form of an injection in the buttocks or arm once every three months. It works by suppressing ovulation, or preventing the ovaries from releasing an egg. In addition, it thickens cervical mucus so that if an egg is somehow released, the sperm will have great difficulty in reaching it. What are your chances of getting pregnant when having depo? Is it really effective to prevent pregnancy?
What Are the Chances of Getting Pregnant on Depo?
The depo shot is very effective as long as you get the shot every 12 weeks, before the protection window expires. Less than one of every 100 women will get pregnant if the schedule is kept. About 6 of 100 women will get pregnant each year if they don't strictly follow the schedule. If you get the depo spot within the first seven days after you start your period, you will be protected immediately. If you choose to get the shot within three weeks after giving birth or within five days after a miscarriage or abortion, you are also protected from pregnancy immediately. However, if you choose to get the shot at any other time, you will need to use another birth control method for the first week.
Always remember to go back to get the shot 12 weeks later. If you are a few weeks late in getting your shot, you might have to take a pregnancy test to ensure that you can get another shot. Remember that though depo is effective in preventing pregnancy, it can't protect you from sexually transmitted infections.
How Effective Are the Other Birth Control Methods?
Besides the chances of getting pregnant on depo, here are the chances of pregnancy with other birth control methods.
Type |
Method Used |
Chances of Unplanned Pregnancy (Actual Use) |
Chances of Unplanned Pregnancy (Perfect Use) |
Hormonal |
Transdermal patch |
9% |
<1% |
Hormonal implant |
<1% |
<1% |
|
Vaginal ring |
9% |
<1% |
|
Combination birth control pills |
9% |
<1% |
|
Progestin-only pills (mini-pills) |
9% |
<1% |
|
IUD |
Copper IUD |
<1% |
<1% |
Hormonal IUD |
<1% |
<1% |
|
Barrier Methods |
Male condom |
18% |
2% |
Female condom |
21% |
5% |
|
Pulling out |
22% |
4% |
|
Spermicide |
28% |
18% |
|
Diaphragm with spermicide |
12% |
6% |
|
Sponge with spermicide (after childbirth) |
24% |
20% |
|
Sponge with spermicide (no previous childbirth) |
12% |
9% |
|
Cervical cap (no previous childbirth) |
16% |
9% |
|
Cervical cap (after childbirth) |
32% |
26% |
|
Surgery |
Tubal ligation or implants |
<1% |
<1% |
Vasectomy |
<1% |
<1% |
|
Fertility awareness |
Fertility awareness methods and periodic abstinence |
24% |
5% |
No birth control |
None |
85% |
85% |
How to Choose the Best Birth Control Method
How do you know which birth control is best? Now that you know the chances of getting pregnant on depo and other birth control methods, it’s time to think about how to choose between them.
- If you want the most effective methods, hormonal methods are the best, as they tend to be the safest in preventing pregnancy. They can also be used long-term, such as the Pill, patch or vaginal ring.
- If you want to have fewer periods, certain pills allow for extended time between periods. These pills can be prescribed by your doctor. In most cases, you can expect to have three or four periods a year.
- If you want to ensure contraception won’t fail, emergency contraception can help. If you realize you have missed a few pills, forgot to insert your diaphragm, used a broken condom, or have anything else that makes you feel unsafe, emergency contraception can be kept on hand.
- If you want to continue smoking, you might want to forgo birth control pills. The best option for you would be an intrauterine contraceptive device.
- If you want to prevent STIs, barrier methods are the only way to go. Use a condom every time if you are unsure of your partner’s history or current actions, if either of you already has an STI, or if you are worried that your partner is not faithful.
- If you have just given birth, condoms, IUCDs and progestin-only contraceptives are the best bet, as they do not affect your breast milk production. If you used a diaphragm or cervical cap in the past, it must be refitted after your delivery to ensure proper protection.
- If you want to have another child, just not right now, you can look to natural methods of birth control in conjunction with condoms or other barrier methods. This allows you to have sex only when your chances of fertility are low, and you are still protected. And when you do choose to have a child, you can begin trying immediately.
- If you have had an abortion, you might want to look into something much more effective than what you were using when you got pregnant. Your chances of getting pregnant on depo are relatively low, so that might work well. Long-term protection can be obtained through the IUCDs. If you are certain you do not want more children, a tubal ligation or implant can help ensure you do not get pregnant.
- If you are heading toward menopause, low-dose birth control pills can help prevent pregnancy during those rare times you do ovulate. They can also help with some of the hormonal swings you are dealing with during the years leading up to menopause.