The contraceptive injection, explained

The contraceptive injection is a common method in South Africa. You do not have to remember anything daily. You only need to come back on time for your next injection. This guide from Network One Health explains the two types and what to expect.

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Two types of injection

Both injections contain only a progestogen. There is no oestrogen.

• DMPA (depot medroxyprogesterone acetate), often called Depo. You have it every 12 weeks. The usual type, DMPA-IM, is given into a muscle in your upper arm or buttock. A lower-dose type, DMPA-SC, is given just under the skin. WHO notes it can be given in the tummy, thigh or upper arm.
• NET-EN (norethisterone enanthate), often called Nur-Isterate. You have it every 8 weeks, into a muscle in your upper arm or buttock.

The two types should not be swapped back and forth. If you need to change from one to the other, do it when your next injection is due.

How well it works

Out of 100 women using the injection for a year, about 6 get pregnant with typical use (South African guideline; WHO 2025 estimates 4 in 100). With perfect use, fewer than 1 does (both sources agree). The difference comes mostly from late injections.

The injection does not protect against STIs or HIV. Use condoms as well if you may be at risk.

Starting the injection

• If you have your first injection within 7 days of the first day of your period, you are protected straight away.
• At any other time, your clinician needs to be reasonably sure you are not pregnant. Then use condoms or do not have sex for the next 7 days.

Coming back on time

Try to come back on the date you are given. You can have your next injection up to 2 weeks early.

If you are late, you still have a window:

• DMPA (12-weekly): you can have your injection up to 4 weeks late and still be protected.
• NET-EN (8-weekly): you can have your injection up to 2 weeks late and still be protected.

This window is a safety net, not a new schedule. Do not plan to come late.

If you are later than this, still come in. Do not stay away. Your clinician will check that you are not pregnant before giving the injection. You will then need condoms, or no sex, for the next 7 days. If you had sex without a condom recently, ask about emergency contraception.

What happens to your periods

Changes to your bleeding are the most common side effect. You may have:

• irregular bleeding or spotting, especially after the first injection
• no periods at all
• heavier or longer bleeding, especially in the first injection cycle

None of these is harmful in itself. Having no periods does not need treatment. If the bleeding bothers you, a clinician can offer short-term treatment, or help you change methods.

See a clinician if bleeding lasts more than 8 days, or is twice as heavy as your usual period.

Getting pregnant after you stop

With most methods, fertility returns soon after stopping. The injection is different.

After your last injection, it can take 6 to 12 months for your fertility to return. It does return. The injection does not cause permanent infertility.

If you are planning a pregnancy within the next year, talk to your clinician. Another method may suit you better for now.

Bone health

While you use DMPA, it lowers bone density slightly. Bone density is a measure of how strong your bones are.

• Research suggests this bone loss appears to be reversible after you stop.
• The World Health Organization has concluded that this does not mean there is a limit on your age or on how long you use DMPA.
• For young women still building bone, this is something to discuss with your clinician.
• There is less evidence for NET-EN, but it is possibly less likely to affect bone density.

Women who use DMPA are usually advised to stop it at age 50 and change to another method.

Other medicines

DMPA keeps working well with HIV medicines, TB medicines and epilepsy medicines. That is one reason it is often offered to women taking these medicines.

NET-EN may work less well with some of these medicines. There is limited information. Always tell your clinician about every medicine you take.

Your risk of HIV does not limit which contraceptive method you can choose. A large study found no difference in HIV risk between women using DMPA, the copper IUD or the implant.

Privacy

The injection leaves nothing to keep at home. Many women value that.

When to see a clinician

• You think you might be pregnant
• You are late for your injection and have had sex without protection
• Bleeding is very heavy or goes on for more than 8 days
• You want to stop, or change to another method

Where to get the injection

Contraception, including the injection, is available at public clinics in South Africa.

What to expect at Network One Health

At Network One Health, we explain the bleeding changes and the fertility delay before your first injection, so nothing comes as a surprise. If the injection stops suiting you, we will help you choose another method.

Booking and questions: WhatsApp Noma on 065 072 5315.

Emergencies: If you think you have a medical emergency, go to the emergency unit at your nearest hospital or call 10177.