Fertility After Injectables

Fertility returns more slowly after progestin-only injectables than after pills, implants, intrauterine devices or barrier methods. Ovulation is delayed for four months or longer after the last injection, and in some patients for up to 12 months. The delay does not depend on how long the injectable was used, and it does not mean permanent infertility.

Why the delay occurs. The depot releases hormone slowly, so ovulation remains suppressed for the interval and for a variable period after it. Return of ovulation is unpredictable in the individual patient.

Products. DMPA 150 mg intramuscular and 104 mg subcutaneous every 13 weeks; norethisterone enanthate 200 mg intramuscular every 8 weeks. Combined injectables (given every 30 days) allow ovulation to return after about 5 months on average.

Counselling point. Women who want to conceive within a year should choose another method.

Comparison. Fertility returns at once after pills, implants and intrauterine devices, and after about 5 months on average with combined injectables.

Patients to counsel. Anyone planning pregnancy in the near future, women who are older, women with other fertility risk factors, and young women who may want a child soon after stopping.

History. Record the product, the date of the last injection, the length of use, previous cycle pattern, age, parity, previous pregnancies, weight and any pelvic infection, thyroid disease, polycystic ovary syndrome or endometriosis.

Pregnancy exclusion. Amenorrhoea after stopping does not exclude pregnancy. Do a pregnancy test when menses are absent after unprotected sex, because pregnancy can occur before the first bleed.

Choice of method for those planning pregnancy. Do not start an injectable. Offer pills, an implant, an intrauterine device or condoms, all of which allow a prompt return of fertility.

Counselling. Explain that the average delay is four months or longer, that it varies, and that prolonged delay should be investigated if it exceeds the expected range. Obtain consent and protect confidentiality. Adolescents under 18 years give assent.

Stopping. The patient stops by not having the next injection. No washout treatment is given. If pregnancy is not wanted yet, move to another method at the due date of the next injection: pills or an implant started when the injection is due, or an intrauterine device inserted within 7 days of menses.

Planning conception.

• Use condoms from the due date of the next injection until pregnancy is wanted if conception should be delayed.
• Folic acid 400 microgram orally daily from before conception until 12 weeks of pregnancy (a higher dose applies to women at high risk of neural tube defects, on antiseizure medicines, or with diabetes or obesity).
• Review HIV status, blood pressure, diabetes control, immunisation, medicines that are unsafe in pregnancy, smoking and alcohol.
• Cycle charting or ovulation prediction may help once menses return.

Expected timing. Menses and ovulation usually resume within about four months of the expected end of the injection interval. Most patients conceive within 12 months of stopping, and nearly all within two years.

Follow up. Review at 6 months after the last injection if no menses have returned and at 12 months if conception has not occurred, or earlier for women aged 35 years or more.

Expected effects. Persistent amenorrhoea, irregular cycles and delayed ovulation in the first months after stopping. Weight changes and mood symptoms may persist briefly.

Prolonged delay. If menses do not return by about 6 months after the last injection:

• Do a pregnancy test.
• Check thyroid function, prolactin, follicle-stimulating hormone and luteinising hormone, and oestradiol.
• Review weight, exercise, stress, eating disorders and medicines.
• Consider polycystic ovary syndrome, premature ovarian insufficiency and uterine causes such as intrauterine adhesions.

Do not diagnose infertility until at least 12 months after the end of the expected contraceptive interval (6 months in women aged 35 years or more). Underlying tubal disease, ovulatory dysfunction, reduced ovarian reserve and uterine factors may need assessment.

Pregnancy soon after stopping. No special change is needed: confirm the date by ultrasound, give folic acid, and start antenatal care.

Red flags. Severe lower abdominal pain or shoulder tip pain with a positive test (ectopic pregnancy), galactorrhoea, visual field change, features of thyroid disease.

Referral and escalation. Refer to a gynaecologist or fertility service when the delay exceeds the expected range, when the woman is 35 years or older and unsuccessful after 6 months, or when tests suggest ovulatory failure, tubal disease or ovarian insufficiency.