Depo-Provera and Bone Density: Does the Contraceptive Injection Weaken Your Bones?

Yes, the Depo-Provera contraceptive injection can lower bone density, because it reduces the oestrogen your bones need. The loss is usually small and mostly recovers after you stop. UK guidance therefore asks for a review every 2 years, and suggests that under-18s consider other methods first. For most people it remains a safe, effective choice, but it is worth knowing about if you have other risks for weak bones.

What is the Depo-Provera injection?

Depo-Provera is a progestogen-only contraceptive injection containing medroxyprogesterone acetate (DMPA), given into a muscle by a nurse or doctor. UK guidance recommends returning every 13 weeks for the next injection FSRH guideline. A lower-dose version, Sayana Press, is injected under the skin and can be self-injected after training. The bone advice in this article applies to both forms.

The injection works mainly by stopping ovulation emc SmPC. It is very effective and you don't have to remember a daily pill, which is why many people choose it.

Does the contraceptive injection cause bone loss?

Yes. The injection lowers oestrogen levels, which causes a small loss of bone mineral density in many users. The NHS states: "Using the contraceptive injection for more than 1 year can cause your bones to become weaker" NHS. UK sexual health guidance describes it as "a small loss of bone mineral density, which is usually recovered after discontinuation" FSRH guideline.

The product information gives figures from clinical studies emc SmPC:

• Adults (intramuscular injection): average lumbar spine changes of -2.9% after 1 year, -4.1% after 2 years and -5.4% after 5 years. At 5 years, the total hip had fallen by 5.2% and the femoral neck by 6.1%.
• Teenagers (4.6 years of use): total hip down 6.4%, femoral neck down 5.4% and lumbar spine down 2.1%.

The FSRH guideline notes that bone loss tends to be fastest in the first year and then slows down.

Does the injection increase fracture risk?

It is not clear. Studies have not shown whether the loss in bone density leads to more broken bones. The FSRH guideline says the clinical significance of the bone changes "is unclear" and it is not known whether this translates into a higher fracture risk FSRH guideline.

Some observational studies found slightly more fractures in injection users. However, one study described in the FSRH guideline found these users already had a higher fracture risk before starting. Their extra fractures were mostly in fingers, toes and the face rather than the hip or pelvis. The authors suggested the difference reflected who chose the method rather than the injection itself FSRH guideline.

Does bone density recover after stopping Depo-Provera?

Mostly, yes. Bone density usually climbs back towards normal after stopping, although in some people this takes years and may not be complete. The NHS says "your bones are likely to return to normal after you stop having contraceptive injections" NHS.

The product information gives more detail emc SmPC:

• Teenagers: bone density returned to baseline after about 1.2 years at the spine and 4.6 years at the hip. Some participants did not fully recover, and the long-term outcome for them is unknown.
• Adults after 5 years of use: two years after stopping, bone density had risen at all three sites "but deficits remained" (for example, the spine was still 3.1% below baseline).

For women who use the injection right up to the menopause, the FSRH guideline notes studies suggesting no significant extra loss after the menopause compared with non-users FSRH guideline.

Can under-18s use the Depo injection?

Yes, but only after other contraceptive options have been discussed, because teenagers are still building their peak bone mass. The FSRH supports MHRA advice that "in women aged under 18 years DMPA may be used as first-line contraception after all options have been discussed and considered unsuitable or unacceptable" FSRH guideline.

The product information explains why: the loss "is of particular concern during adolescence and early adulthood, a critical period of bone accretion" emc SmPC. Our guide to building peak bone mass explains what helps young people bank as much bone as possible.

Why is a review every 2 years recommended?

UK guidance asks anyone who wants to stay on the injection to have their risks and benefits reassessed every 2 years. The FSRH supports MHRA advice that "a re-evaluation of the risks and benefits of treatment for all women should be carried out every 2 years in those who wish to continue use" FSRH guideline. Long-term users should be reviewed at least every 2 years by a prescriber.

This is a conversation, not an automatic stop. The guideline also says:

• Women with significant risk factors for osteoporosis should consider other methods.
• Women are generally advised to switch method at 50, though continuing may be considered after a discussion of the risks.
• For women over 40, the advantages of the injection generally outweigh the risks.

The product information lists the main risk factors to raise at your review: heavy drinking or smoking, long-term steroid or anti-epileptic medicines, low body weight or an eating disorder, a previous fracture from a minor fall, and a family history of osteoporosis emc SmPC. Our guide to medicines that cause bone loss covers other medicines that can affect bone. If low weight or intense training applies to you, see RED-S and bone health.

What are the other side effects of the Depo shot?

The most common side effects are changes to your periods and weight gain. There are also some rarer risks to know about. The NHS lists NHS:

• Period changes: periods may stop, become irregular or last longer. The longer you use it, the more likely your periods are to stop completely.
• Weight gain. The FSRH guideline notes it is particularly linked with under-18s who have a BMI of 30 or more.
• Slightly higher risk of breast and cervical cancer, which the NHS describes as very small and likely to fall after stopping.
• A possible increased risk of blood clots. People with a past clot may be advised to use another method.
• A small increased risk of a benign brain tumour called a meningioma. The product information says the medicine must be stopped if a meningioma is diagnosed.

Fertility can take a while to return. The product information says the return of ovulation "may be delayed for up to one year" emc SmPC, which matters if you plan a pregnancy soon.

What contraceptive alternatives can you discuss?

If bone health is a concern, ask your GP or sexual health clinic about other long-acting or daily methods. Options to talk through include the contraceptive implant, the hormonal coil (IUS), the copper coil (IUD), progestogen-only or combined pills, the patch and the ring. The right one depends on your health, your periods and your preferences. A clinician can explain how each affects you.

How can you protect your bones while using the injection?

Get enough calcium and vitamin D, stay active with weight-bearing exercise, and avoid smoking and heavy drinking. The product information stresses that adequate calcium and vitamin D, from diet or supplements, matter for bone health at all ages emc SmPC. Our guides to vitamin D, calcium and protein, the best exercises for bone health and smoking and bone health cover the practical steps.

Bone scans are not routine for injection users. The FSRH says there is insufficient evidence to recommend them and that clinicians should follow local referral criteria FSRH guideline. If you have used the injection for many years and have other risk factors, raise it with your GP. Some people also choose a radiation-free bone health assessment from Screen My Bones as a baseline. It is a screening option, not a replacement for a DXA scan when a doctor needs a formal diagnosis.

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This article is for general information and does not replace advice from your GP, nurse or sexual health clinic. Do not stop or change your contraception without talking to a health professional.