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The Birth Control Shot (Depo-Provera): How It Works, Side Effects & Alternatives

Kristin Hall

Medically reviewed by Kristin Hall, FNP

Written by Our Editorial Team

Last updated 10/26/2020

Long-lasting and effective, Depo-Provera® is an alternative to birth control pills, rings, patches and other forms of hormonal contraception. 

Better known as the birth control shot, Depo-Provera uses a progestin hormone to prevent you from becoming pregnant. It works similarly to birth control pills and other forms of contraception that use hormones to prevent pregnancy.

If you don’t like the idea of using a patch, ring or taking a pill every morning, the shot is an easy, convenient option for staying protected.

Like every form of birth control, the Depo-Provera shot has its own range of unique advantages and disadvantages. It also has its own set of potential side effects, many of which are similar to those of the pill, patch and ring.

Below, we’ve explained how Depo-Provera works, as well as the potential side effects you might experience while using it. We’ve also compared it to other hormonal birth control options to help you choose the best form of birth control for your needs, lifestyle and health requirements.

How Does Depo-Provera Work?

The Depo-Provera shot uses a progestin hormone called depot medroxyprogesterone acetate, or DMPA, to stop you from becoming pregnant. 

As a contraceptive, Depo-Provera works by stopping you from ovulating, as well as changing the thickness of your cervical mucus. This makes it more difficult for sperm to travel into your uterus and come into contact with an egg.

Depo-Provera is very effective at preventing pregnancy. Based on study data, the average effectiveness rate of the Depo-Provera injection is more than 99 percent when used perfectly, with less than one woman out of every 100 who use the injection becoming pregnant every year. 

Like other hormonal contraceptives, Depo-Provera becomes less effective if you forget to get the shot on time, with an effectiveness rate of about 94 percent under “real life” conditions.

How Long Does Depo-Provera Last?

Each shot of Depo-Provera lasts for 13 weeks. If you use the shot as your form of birth control, you’ll need to return to your healthcare provider every 10 to 13 weeks for a new injection. If you’re late getting your injection, you could potentially become pregnant from sexual activity and need to follow up with your healthcare provider 

It’s best to schedule an appointment for each new shot one to two weeks in advance to make sure you’re able to maintain steady levels of the medication.

Unlike the pill, patch, ring and other forms of hormonal contraception, Depo-Provera generally isn’t suitable for long-term use. Most healthcare professionals recommend using Depo-Provera for a maximum period of two years at a time for optimal health and wellbeing.

What Happens if You’re Late for the Depo-Provera Shot? 

Like other forms of hormonal birth control, the Depo-Provera injection is only effective if you receive each injection on time. 

On average, Depo-Provera lasts for 12 to 13 weeks before becoming less effective. In some cases, the shot may last for up to 15 weeks, but It’s best not to rely on what “may” work and to schedule your follow-up shot for 10 to 13 weeks after you’ve received your last injection. 

If you forget to get your follow-up injection or you’re late for your injection, you’ll need to use a second form of contraception when you have sex. It’s best to use a form of barrier protection (like condoms) until you receive a new Depo-Provera shot to reduce your risk of becoming pregnant.

Being late for your follow-up shot or missing a shot won’t carry adverse effects for your health, but it does mean that the medication won’t be effective as a form of birth control. 

If you’re late for your follow-up injection, your healthcare provider may ask you to take a pregnancy test before administering the injection. This is to check that you’re not pregnant before you get a follow-up shot of the medication.

Just like the pill, the patch, the ring and other forms of birth control, the most effective way to stay protected against pregnancy with Depo-Provera is to make sure you get every follow-up shot on time. 

Advantages of Depo-Provera

The biggest advantage of Depo-Provera is its convenience. Unlike the pill, which you need to take every day, or the ring, which needs to be changed once every month, you’ll only need to get one Depo-Provera injection every three months to stay protected against pregnancy. 

This makes Depo-Provera a good birth control option if you often forget to take medicine, or if you don’t like the inconvenience of having to swallow a tablet every morning. 

A second advantage of Depo-Provera is the ease of using it properly. While it’s easy to forget about a small birth control tablet and miss a dose, all you need to do to stay compliant with the dosage instructions for Depo-Provera is visit your healthcare provider every three months. 

A third advantage of Depo-Provera is its lack of estrogen. Unlike combined birth control pills, which contain a mix of ethinyl estradiol and a progestin hormone, the Depo-Provera injection only contains a single progestin hormone called depot medroxyprogesterone acetate.

This means that Depo-Provera is less likely to cause estrogen-related side effects than many other forms of birth control.

The Depo-Provera injection can also make your periods lighter and easier to manage. In clinical studies, 55 percent of women stopped getting their period completely while using the shot within the first year, making it a good birth control option if you often get heavy, uncomfortable periods. 

You also have a lower risk of experiencing an ectopic pregnancy if you become pregnant while using the Depo-Provera injection as a form of birth control than you would if using combined hormonal birth control.

Finally, the Depo-Provera shot is temporary. If you decide you want to get pregnant, you’ll be able to do so. In clinical studies, the median time to conception for women who stop using Depo-Provera to become pregnant is 10 months, but conception has been known to happen in as early as four months. 

However, every individual is unique and there is no way to truly know how long it will take for you to get pregnant. 

Disadvantages of Depo-Provera

Depo-Provera also has several disadvantages. One of these is the fact that you’ll need to get an injection in order for the medication to be effective as a form of birth control. 

In general, the Depo-Provera injection isn’t particularly painful or difficult. However, if you have a fear or needles or simply don’t like being injected, you’ll may  prefer using the pill, the ring or another form of birth control. 

This can also be an annoyance if you’re not centrally located to your healthcare provider or live an active, busy lifestyle, as you’ll need to drive to your healthcare provider’s office every three months to get your follow-up shot. 

A second disadvantage of Depo-Provera is its effect on your ability to become pregnant. While the Depo-Provera injection doesn’t stop you from becoming pregnant forever, it can take several months (10, on average) before you’ll be able to conceive after you stop getting the injections. 

This can be a major annoyance if you quickly decide that you’d like to conceive. If you think you would like to become pregnant in the near future but still want to use birth control, you’ll usually get better results from the pill, the ring or any other short-acting form of birth control. 

Another disadvantage of the Depo-Provera shot is that it doesn’t protect you from anything other than getting pregnant. It won’t help protect you against HIV or other sexually transmitted infections like barrier methods do. 

Finally, the Depo-Provera shot isn’t completely free of side effects. While most side effects from Depo-Provera are mild and harmless, Depo-Provera can also have severe side effects when it’s used as a long-term contraceptive. We’ve covered these side effects in more detail below. 

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What are the Side Effects of Depo-Provera?

Most of the side effects of Depo-Provera are similar to those of other types of hormonal birth control. They include:

  • Changes to your period. Some women who use Depo-Provera experience longer or less predictable periods, as well as spotting between periods. You might stop getting your period altogether — a term called amenorrhea — if you use Depo-Provera as your form of birth control.

  • Breast tenderness. The progestin hormone in Depo-Provera can cause your breasts to feel more tender and sensitive than normal. You might also experience a slight increase in breast size while using Depo-Provera.

  • Nausea and headaches. Depo-Provera can cause nausea. This is a fairly common side effect that tends to occur during the first two to three months of use. Many women notice mild headaches during the first few months of using Depo-Provera.

  • Changes in mood. Like other hormonal medications, Depo-Provera has the potential to affect your mood. You might experience symptoms of depression during the first few months of using Depo-Provera.
    If the effects of Depo-Provera on your mood are significant, it’s best to talk to your healthcare provider  about them. You might experience a more stable mood by changing to another form of birth control.

  • Weight gain. While the hormones in Depo-Provera aren’t directly linked to fat gain, they can cause your body to retain more fluid than normal. This can cause you to gain weight.

  • Bone density loss. One of the most serious side effects of Depo-Provera is its potential effect on your bones. If you use Depo-Provera for more than two year, you could lose a significant amount of calcium, affecting the density and strength of your bones.
    Bone loss is usually permanent, meaning it’s important that you’re aware of this potential side effect before using Depo-Provera.
    This is the main reason that Depo-Provera is only recommended for use for a maximum of two years in most women. If you’re at risk of bone density loss, your healthcare provider may also recommend using a vitamin D and/or calcium supplement.

  • Reactions to the injection. Although this isn’t a major issue, it’s common to experience a mild local reaction to the Depo-Provera injection. This ranges from bruising and pain at the injection site to skin reactions such as itchiness and irritation.
    Some women also experience dizziness, fatigue and headache after the Depo-Provera injection. These side effects are temporary and usually resolve a few hours after getting the shot.

  • Difficulty getting pregnant after using Depo-Provera. Finally, although most women can get pregnant within one year after stopping Depo-Provera, about seven percent of women who use Depo-Provera fail to get pregnant within 18 months of stopping.
    If you’re planning to become pregnant in the next 12 to 18 months, it’s usually better to use the pill, the patch, the ring, an IUD or other forms of short-acting birth control rather than Depo-Provera. 

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Alternatives to Depo-Provera

Depo-Provera’s effectiveness and convenience make it a fantastic way to protect yourself from becoming pregnant. However, it’s not the only birth control option available. From the pill to the patch, there are several other ways to help yourself avoid pregnancy:

  • Condoms, as well as other barrier methods of birth control, can significantly reduce your risk of becoming pregnant if used properly. Barrier methods of birth control can also stop you from catching or spreading STDs, which isn’t possible using hormonal birth control.

  • The pill, like Depo-Provera, is effective at preventing pregnancy when used according to the instructions. It’s also significantly less likely to lead to bone health and density issues and conditions such as osteoporosis.
    Although the combined birth control pill is the most common, you can also stop yourself from becoming pregnant using the progestin-only mini-pill. Our guide to the two versions of the pill compares each, with detailed information on effectiveness and side effects.

  • The ring, which fits inside your vagina and releases a small dose of hormones to stop you from becoming pregnant. The ring needs to be changed every month, making it a good option if you prefer something more convenient than the pill.

  • The patch, which attaches to your skin and releases a small dose of hormones into your body. Used properly, the patch is very effective at preventing pregnancy and only needs to be changed once every week.

  • The IUD, which stops you from becoming pregnant by preventing sperm from entering your uterus and, for the hormonal IUD, by potentially stopping your body from ovulating normally.
    Depending on the type and brand of IUD you use, the IUD can stop you from becoming pregnant for up to ten years. It’s removable at any time, making it easy to stop using the IUD for birth control if you decide you want to become pregnant.

Want to learn more about all your birth control options? Check out our complete guide to birth control.

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.