• 99+% effective with perfect use; less than one out of every 100 women will become pregnant each year
• 97% effective with typical use: 8 out of every 100 women will become pregnant each year

Additional Sources for Effectiveness Ratings and Use:

• 97% typical use: Contraceptive Technology, 18th Revised Edition; Hatcher, Trussell, Stewart, Nelson, Cates, Guest, Kowal: Ardent Media, 2004.
• 97% typical use/ 99.7% effective perfect use: Feminist Women's Health Center
• 97% typical use/over 99+% perfect use: Planned Parenthood

The What, the Why, the Where, the When, and the How-to: Depo-Provera, DMPA, or the Shot, is a progestin-only hormonal method of birth control which is injected into a woman's arm or bottom every three months, but which provides highly effective protection against pregnancy every day. The hormone in Depo-Provera prevents pregnancy by thickening cervical mucus, impairing sperm mobility so it's tougher for them to reach an egg in the uterus, as well as by suppressing ovulation, the release of an egg.

So long as women are sure to get their injections on time, Depo is very goofproof: other than getting those shots, there is no possibility of user error. A backup method of birth control is only needed within the first 24 hours of the first injection so long as the injection time is scheduled properly by your healthcare provider.

Because once you get that injection, you not only can't discontinue use for three months, and because side effects of Depo-Provera can continue for many months to even years after use, we also usually advise that women try a more easily reversible method of progestin-only contraception first, like the minipill, before trying Depo. That way, if you find out you and progestin don't do so well together, you won't have to live with side effects you don't like for so long.

Depo use is associated with bone loss, which is a big concern for all women, but particularly for adolescent and young adult women, whose bones have not stopped growing. Ideally, it is likely best for younger women to look to other methods first, and if Depo still turns out to be a sole option or looks like the best one, it's vital that young women be sure and take a calcium supplement and eat calcium-rich foods daily to help protect bones. Depo is also not usually suggested for any women for long-term use because of these bone concerns.

Most women using Depo will gain weight, and for some, substantial amounts of weight. As well, if you're not okay with unexpected bleeding or spotting, or unpredictable or absent periods, the shot probably isn't a good choice for you. Lastly, many women who suffer from depression often say that Depo made their depression worse, even though it isn't specifically contraindicated for depressives.

While many women who cannot use other hormonal methods of contraception, such as smokers, women over 35, and women who are breastfeeding, Depo is not right for all women. Those with Cushing's Syndrome, have had unexplained vaginal bleeding, breast cancer or other issues may not be a good fit for the shot. Be sure to discuss your health history and any current health issues with your healthcare provider so that they can be sure the shot is safe for you to use.

Why would women use Depo-Provera? The benefits of Depo-Provera are that it is a highly effective method with little room for user error, it is a method a person does not have to think about at the time of sex, but only every three months, it decreases menstrual cramping, may cause periods to be scanty or absent, it is not affected by most medications, it can be used by women who cannot or do not want to use hormonal methods with estrogen, because it works within 24 hours after the injection, or because a woman wants a hormonal method, but cannot use methods with estrogen.

To get Depo, you'll need to visit your sexual healthcare provider (who may also be your regular doctor) to have your injections administered. Injections usually cost around $35 - $75.

Some questions and answers about the Depo-Provera shot:

• Depo's website
• Teens taking Depo-Provera can recover lost bone density
• Scarleteen Message Board users talk about their experiences using Depo

When Good Birth Control Does Bad Things: Depo is a highly effective method of birth control, which will usually only fail if women do not get their injections administered on time. For those concerned with weight gain, a large study was recently released which verified that weight gain can be a particular issue with Depo: in that study, women using Depo gained around 11 pounds on average during use, more than with oral contraceptives.

Other methods which can be used as a backup method with Depo-Provera (even though, so long as it is used properly, a backup is not usually needed):

• Cervical Barriers (Diaphragms, Lea's Shield and Cervical Caps)

• Condoms
• Emergency Contraception (Plan B or the Morning-After-Pill)
• Spermicides
• the Sponge
• Withdrawal

Other methods you might like if you like Depo-Provera:

• the Contraceptive Implant (Implanon)
• Intrauterine Devices (IUD, IUC or IUS)
• Progesterone-Only Oral Contraceptives (Minipills)
• the Vaginal Ring (Nuvaring)

Why would Depo be a good option for me? If any of the following are true:

• You want a method which is highly effective and seriously goofproof

• You want some of the possible benefits Depo may offer, like a reduction in menstrual cramps, scanty or absent periods, weight gain (if you see that as a benefit),
• You want a very private method of birth control
• You want to only have to remember to use your method every three months
• You can commit to calcium supplements, as well as to getting to your healthcare provider for a new injection every three months
• You don't want a method you have to think about at the time you're going to have sex

For a very brief overview of all BC methods, have a look at Margaret Sanger's Disneyland: Choosing Contraceptives.

This is part of Scarleteen's Birth Control Bingo. Need to start over or anew? Click here.

Don't forget: Statistically, sexually active young adults are as, if not more, likely to acquire a sexually transmitted infection (STI) as you are to become pregnant. Although 15-24-year-olds represent only one-quarter of the sexually active population, they account for nearly half of all new STIs each year, and of the 18.9 million new cases of STIs each year, 9.1 million (48%) occur among 15-24-year-olds (AGI). Often people have some funny ideas about who is most likely to get an STI, but the fact of the matter is that younger people -- of any sexual orientation, any economic class, any kind of relationship -- have been the highest risk group for some time now.

Condoms are the only method of birth control which also provide protection against STIs. It's pretty typical for younger people to ditch condoms if they have another method of birth control, so just remember that STIs are still a risk if you're using another method. You can read all about safer sex here -- Safe, Sound & Sexy: A Safer Sex How-To -- but the rule of thumb most medical experts and prevention organizations suggest, which we also encourage at Scarleteen is six months of safer sex, six months of sexual monogamy, and then TWO full STI screenings for each partner -- once at the start of that six months, once at the end -- before ditching latex barriers.