Medically reviewed by Sophia Yen, MD, MPH – Written by Pandia Health Editorial Team

First of all, what is the Shot (for birth control) ?

The shot or Depo-Provera is a birth control method in which someone with a uterus gets an injection every 12 weeks. The shot contains the drug depot medroxyprogesterone acetate. It is a synthetic progestin that blocks ovulation and prevents pregnancy. The depo-shot is a low maintenance: you indeed only have to think about it every 12 weeks! It is also a highly effective form of long term birth control.

How does the shot work?

The shot is 99% effective. Most women go to a provider to receive the injection. You can also self-administer it but few women do.

What are the side effects from the birth control shot?

The most common side effects are: the munchies and irregular bleeding.

Other less common side effects include headaches, breast tenderness, depression, and potential transient bruising at the injection site.

Effect on bone density

In addition to these side effects, the depo-shot decreases bone density. Bone density loss increases bone fragility. As a result, depo-shot users are more at risk of breaking and fracturing bones.

Besides, you are at greater risk for developing osteoporosis when using the depo-shot if: you smoke, are thin or small framed, have prior broken bones, come from Caucasian or Asian ancestry, have a family history of osteoporosis, are approaching menopause, or have a diet low in calcium.

However, the Society for Adolescent Medicine’s Depo-Provera guidelines state that the duration of use does not need to be restricted to 2 years. Similarly, the World Health Organization’s (WHO) and American College of Obstetricians and Gynecologists’ (ACOG) guidelines do not place any restrictions on the length of Depo use in women aged 18-45. Finally, the Practice Committee of the American Society for Reproductive Medicine does not recommend BMD (Bone Mineral Density) testing of Depo users.

In 2004, the FDA gave the depo-shot a black box warning to warn patients and health care providers that the depo-shot causes bone density loss. However, according to a study by the National Institute Health in 2005, the bone loss caused by the depo-shot was reversed after injections were stopped for 1 year. Another 2010 study showed that for some people needed up to 5 years after stopping injections to attain normal bone density.

TLDR: If you use the shot, make sure you get enough Calcium and Vitamin D and weight bearing exercise. All of those help maintain bone density.

Need a birth control prescription? Pandia Health’s doctors prescribe birth control pills, the patch, and ring as well as Emergency Contraception pills. Sign up now and take control over the birth control that works for you!

Want to read more?

For more information about the depo-shot, you can also give these a read:

Guilbert E, Brown J, Kaunitz A et al., “The use of depot-medroxyprogesterone acetate in contraception and its potential impact on skeletal health,” Contraception 2009; 79(3):167-77.

Tolaymat L, Kaunitz, “Use of Hormonal Contraception in Adolescents: Skeletal Health Issues,” Current Opinion in Obstetrics & Gynecology 2009; 21(5):396-401.

Practice Committee of the American Society for Reproductive Medicine, “Hormonal Contraception: Recent Advances and Controversies,” Fertil Sterl 2008; 90:S103-13.

Harel Z, Johnson C, Gold M et al., “Recovery of bone mineral density in adolescents following the use of depot medroxyprogesterone acetate contraceptive injections,” Contraception 2010; 81(4):281-291.

The above information is for general informational purposes only and is NOT a substitute for professional medical advice. Always seek the advice of your doctor/primary care provider before starting or changing treatment.