DMPA Intramuscular Injection

Depot medroxyprogesterone acetate (DMPA) intramuscular is a progestin-only injectable containing medroxyprogesterone acetate 150 mg as a suspension, given by deep intramuscular injection every 13 weeks. It contains no oestrogen, does not reduce milk supply and is discreet.

Mechanism. Suppresses ovulation by inhibiting gonadotrophin release, thickens cervical mucus and thins the endometrium.

Pharmacokinetics. The depot releases slowly, keeping ovulation suppressed for the full interval and beyond the grace period.

Effectiveness. Typical use: 4 pregnancies in 100 women in the first year. Perfect use: 0.2 in 100. Risk is highest when an injection is late or missed.

Onset and return to fertility. Protection is immediate if given within 7 days of menses; otherwise backup is needed for 7 days. Return of fertility is delayed for four months or longer after the last injection, and up to 12 months in some patients.

Non-contraceptive benefits. Amenorrhoea helps iron-deficiency anaemia. The method also reduces endometriosis symptoms and lowers the risk of endometrial cancer and fibroids.

Ideal candidates. Patients who want a private, no-daily-action method, breastfeeding women from 6 weeks, those on enzyme-inducing medicines, and those with sickle cell disease or epilepsy.

Assessment. Menstrual, obstetric and medicine history, blood pressure, and breastfeeding status. Pelvic examination, breast examination and laboratory tests are not required. Routine bone density testing is not needed. Offer HIV testing.

Pregnancy exclusion. Reasonably certain if any of: baby under 6 months, fully breastfeeding and no menses; delivery within 21 days; no sex since the last normal period; within 5 days of menses; within 5 days of abortion; negative test with no unprotected sex for 3 weeks; consistent correct use of a reliable method. Otherwise test; quick start with backup for 7 days is acceptable after a negative test, with a repeat test when 3 weeks have passed since the last unprotected sex.

Eligibility categories.

• Category 1: BMI 30 or more; smoking; HIV; epilepsy and rifampicin or rifabutin use; sickle cell disease; mild compensated cirrhosis; viral hepatitis; breastfeeding from 6 weeks.
• Category 2: under 18 years or over 45 years; high HIV acquisition risk; controlled hypertension or blood pressure of 140 to 159 over 90 to 99 mm Hg; past deep vein thrombosis; uncomplicated diabetes; migraine; antiretroviral therapy with efavirenz, nevirapine or ritonavir-boosted regimens.
• Category 3: breastfeeding under 6 weeks; ischaemic heart disease or stroke; multiple arterial risk factors; diabetes with vascular disease; blood pressure 160/100 mm Hg or more; acute deep vein thrombosis or pulmonary embolism; severe cirrhosis or liver tumour; unexplained bleeding before evaluation; lupus with positive or unknown antiphospholipid antibodies; past breast cancer.
• Category 4: current breast cancer.

Counselling. Consent, confidentiality, absence of coercion. Adolescents under 18 years give assent. Explain bleeding change, weight change, delayed fertility, slight bone density reduction without an age or duration limit, and condoms for infection protection.

Regimen.

• Medroxyprogesterone acetate 150 mg suspension, deep intramuscular injection, every 13 weeks. Shake well before drawing up.
• Start within 7 days of menses without backup; later, backup for 7 days.
• Grace window: up to 2 weeks early and up to 4 weeks late without backup.
• Over 4 weeks late: exclude pregnancy (a test may be needed because amenorrhoea is common), inject, and use backup for 7 days.
• Switching from another hormonal method used correctly: inject at once without overlap. From norethisterone enanthate, inject when the repeat injection is due.
• No dose change for body weight, liver disease or enzyme inducers.
• Use a new disposable syringe and needle, wash hands, dispose of sharps safely. Do not rub the site.

Start timing.

Special groups.

• Adolescents: use is allowed; assent under 18 years, consent in line with the law.
• Epilepsy on enzyme inducers, or tuberculosis on rifampicin or rifabutin: no change in dose or interval.
• HIV: use with any antiretroviral regimen; add condoms.
• Sickle cell disease and iron-deficiency anaemia: amenorrhoea is a benefit.
• Where visits are hard to keep, subcutaneous DMPA with self-injection removes the barrier.

Follow up. Reinject every 13 weeks. Review at each visit for bleeding, blood pressure and weight, with a full review at least yearly. Condoms for infection protection.

Expected effects. Bleeding changes (irregular in the first 6 to 8 months, then amenorrhoea in most by one year); weight change; headache; dizziness; mood swings; bloating; acne; breast tenderness.

Bleeding management.

• Persistent spotting with no pathology: ibuprofen 400 to 800 mg orally three times daily with food for 7 to 14 days, maximum 2400 mg in 24 hours; avoid in peptic ulcer, renal impairment, severe liver disease and NSAID-sensitive asthma.
• Heavy or prolonged bleeding (over 8 days, or twice usual length): exclude gynaecological disease, then give ibuprofen 400 to 800 mg orally three times daily with food for 7 to 14 days (maximum 2400 mg in 24 hours) or a combined oral contraceptive, one active tablet daily for 1 to 3 cycles, if oestrogen is not contraindicated and not breastfeeding under 6 months.
• If 8 weeks or more have passed since the last injection, an early repeat injection with a new return date may induce amenorrhoea.
• If bleeding stays unacceptable or threatens health, stop and offer another method.

Other problems. Amenorrhoea needs only reassurance; test for pregnancy if in doubt. Headache: check blood pressure; stop and refer if severe. Breast tenderness: test for pregnancy, reassure, give analgesia, refer any lump.

Red flags. Severe lower abdominal pain (exclude ectopic pregnancy), jaundice, chest pain, calf swelling, severe headache.

Referral and escalation. Refer unexplained bleeding for examination and cervical screening. Refer pregnancy for antenatal care after stopping the method.