Monthly or 3-Monthly Injection

The difference between the two forms

3-monthly injection (DMPA):

• Contains progestin only.
• Given every 12–13 weeks.
• Can be given into a muscle (150 mg) or under the skin (104 mg).
• With typical use, the first-year pregnancy rate is about 6%. If given on time, this drops to 0.2%.
• Periods usually become lighter or stop.

Monthly injection (for example, medroxyprogesterone + estradiol cypionate):

• Contains both estrogen and progestin.
• Given every 28–30 days.
• Periods may be more predictable.
• In Turkey, it is less widely available than the 3-monthly form.
• Because it contains estrogen, its thrombosis risk is similar to the combined pill.

At SoftCare, which form is suitable is decided based on your history, breastfeeding status and thrombosis risk.

How it works

Progestin suppresses ovulation. If no egg is released, pregnancy cannot occur. Cervical mucus also thickens, making it harder for sperm to pass. The endometrium becomes thinner. The estrogen in the monthly form helps keep periods regular. The effect depends on the injection interval. If you are late, protection decreases.

Who it is suitable for

• Those who forget to take a pill every day
• Those who do not want an IUD
• Breastfeeding women (3-monthly form)
• Those who cannot use estrogen (3-monthly form)
• Those who want lighter periods

Situations that need care:

• Patients with low bone density or a high risk of fractures (if the 3-monthly form will be used long term)
• Uncontrolled high blood pressure or migraine with aura (with the monthly form)
• Active breast cancer
• Unexplained vaginal bleeding
• Suspected pregnancy

The CDC US MEC 2024 criteria are used. The 3-monthly form is category 1 or 2 in many situations. The monthly form follows rules similar to the combined pill.

How it is given

A pregnancy test is done before the injection. It can be started on any day of the cycle, as long as pregnancy is ruled out. If the first injection is given within the first 7 days of your period, it is effective immediately. At other times, condoms are used for the first 7 days.

3-monthly form:

• Given into the muscle of the buttock or upper arm.
• The subcutaneous form can be given in the lower abdomen.
• The next injection is given at week 12–13. If more than 14 weeks have passed, a pregnancy test is needed.

Monthly form:

• Given every 28–30 days.
• If it is more than 3 days late, backup protection is needed.

Mild pain or bruising after the injection is normal. You can have sex the same day. At SoftCare, the date of your next appointment is given to you in writing.

Changes in bleeding

This is the most common change with the 3-monthly form. In the first 3 months:

• About 30% stop having periods.
• About 30% have spotting or irregular bleeding.
• By the 2nd year, the rate of amenorrhea rises to about 70%. Bleeding usually decreases. If spotting is bothersome, short-term treatment can be discussed. Heavy bleeding is rare.

With the monthly form, periods may be more regular. Even so, spotting may occur in the first months. Amenorrhea does not mean pregnancy; if in doubt, a test is done.

Side effects

Common with the 3-monthly form:

• No periods or spotting
• Weight gain (an average of 1.5–4 kg in the first year)
• Headache
• Mood changes
• Lower libido

Bone density:

• Bone mineral density may decrease with long-term use.
• The loss usually recovers partly or fully after stopping.
• With use for more than 2 years, full recovery may not occur in everyone.
• WHO, CDC and ACOG do not restrict use beyond 2 years if there are no other risk factors. At SoftCare, if long-term use is planned, calcium, vitamin D and exercise are discussed. A bone density scan is done if needed.

Side effects of the monthly form are similar to the combined pill:

• Nausea
• Breast tenderness
• Thrombosis risk (at the level of the combined pill)

Seek urgent care for chest pain, shortness of breath, leg swelling or a sudden headache.

Return of fertility

After stopping the 3-monthly form, ovulation may be delayed. It returns within 6–10 months on average. In some women it can take up to 18 months. This delay does not mean permanent infertility. If you are planning a pregnancy, this timeframe is discussed in advance.

With the monthly form, fertility usually returns within 2–3 months. At SoftCare, if a pregnancy is planned soon, a short-acting method is recommended instead of the injection.

Breastfeeding

The 3-monthly form can be used while breastfeeding. It does not affect milk supply. It can be started 6 weeks after giving birth. Because the monthly form contains estrogen, it is not preferred in breastfeeding women in the first 6 months.

How it differs from the gold IUD and other methods

At SoftCare, the gold IUD is our first choice. The injection may be preferred in these situations:

• A patient who forgets the pill and does not want an IUD
• A breastfeeding patient who wants the 3-monthly form
• A patient who wants lighter periods

The gold IUD is hormone-free and fertility returns quickly. With the injection, the return of fertility may be delayed. The hormonal IUD reduces bleeding and carries no risk of forgetting. The implant is effective for 3 years. The injection requires appointments. It does not protect against STIs; a condom should be added. The decision is based on risk of forgetting, bone health and pregnancy plans.

Follow-up

• The date of the next injection is clearly written down
• Bleeding check in the first 3 months
• Annual gynecological examination
• Bone health is discussed with 3-monthly use for longer than 2 years
• Weight monitoring
• STI testing if there is a risk

At SoftCare, patients who receive an injection are given their appointments and urgent care criteria in writing.

Our approach at SoftCare

At SoftCare Clinic, assessment for the injection starts with your gynecological history, breastfeeding status and bone risk. The gold IUD is our first recommendation; the injection is discussed with patients who do not want an IUD or for whom it is not suitable. The 3-monthly or monthly form is chosen. The injection is given in the clinic. Your next appointment is given in writing. With long-term use, bone health is monitored. If a pregnancy is planned soon, another method is recommended. If there is an STI risk, condoms and testing are recommended.

Appointments: +90 212 241 30 10 · softcareclinic.com

References

• 1. Centers for Disease Control and Prevention (CDC). U.S. Medical Eligibility Criteria for Contraceptive Use, 2024.
• 2. UpToDate. Depot medroxyprogesterone acetate (DMPA): Efficacy, side effects, metabolic impact, and benefits.
• 3. American College of Obstetricians and Gynecologists (ACOG). Progestin-Only Hormonal Birth Control.
• 4. World Health Organization (WHO). Medical eligibility criteria for contraceptive use.
• 5. Merck Manual. Progestin Contraceptive Injections.
• 6. FDA. Depo-subQ Provera 104 prescribing information.
• 7. T.C. Sağlık Bakanlığı. Gebeliği Önleyici Yöntemler.
• Note: Injection intervals and bone density monitoring are updated by the physician in line with current guidelines. At SoftCare, the gold IUD is our first choice; the injection is discussed with selected patients. This reference list is for information purposes.

A citation does not mean that SoftCare wrote that text.

Medically reviewed by Op. Dr. Şükrü Sanus, Obstetrician & Gynecologist · Last medical review: 2 October 2026