Excluding Pregnancy Before Contraception

Reasonable certainty is the clinical judgement, made with a short checklist and a pregnancy test where needed, that a patient is not pregnant at the time a contraceptive method starts. It does not require a normal period or a laboratory test. It replaces the habit of sending patients away to return during menses, which causes avoidable unintended pregnancies.

Why it matters. Hormonal contraception started in early unrecognised pregnancy does not harm the foetus. The real risks are delay (unintended pregnancy while waiting) and, for IUD insertion and sterilisation, procedure in an existing pregnancy.

Absolute certainty is not required. For pills, patch, ring, injectables and implants a small residual risk of early pregnancy is acceptable. For IUD insertion and sterilisation the threshold is stricter.

Checklist. Reasonable certainty exists when there are no symptoms or signs of pregnancy and at least one of the following applies.

Pregnancy testing. A sensitive urine test detects pregnancy from about the first day of a missed period, roughly 10 days after conception. A negative result within 3 weeks of unprotected sex does not exclude pregnancy. Test when no checklist item applies, when the checklist is answered no to every question and pregnancy remains possible, when it is 6 weeks or less since the last menses, and when pelvic examination is equivocal (obesity, fibroids).

Pelvic examination and ultrasound. Bimanual examination is unreliable under 6 weeks from the last menstrual period and in obesity. Use a sensitive urine test or ultrasound when available and affordable.

Postpartum. Ovulation can return from about 25 days after birth in non-breastfeeding women, so amenorrhoea beyond 21 days postpartum is not proof that pregnancy is impossible when intercourse has occurred. After 6 months, or once menses return, breastfeeding no longer gives reliable protection.

Steps.

• Ask the checklist questions in a private setting.

• If any criterion is met, provide the method.

• If none is met, do a pregnancy test. If negative and the last unprotected sex was more than 3 weeks ago, provide the method.

• If unprotected sex occurred in the last 5 days, offer emergency contraception first: copper IUD (also an ongoing method) or levonorgestrel 1.5 mg orally as a single dose, or ulipristal acetate 30 mg orally as a single dose.

• If the test is negative but unprotected sex occurred within 3 weeks and the patient declines emergency contraception, give condoms and abstinence advice, or start a method other than an IUD with backup for 7 days, and repeat the test 3 weeks after the last unprotected sex.

• If testing is unavailable, advise condoms or abstinence until menses or pregnancy is confirmed, and provide pills or injectables to start with menses.

Advance supply. A patient who cannot yet be certain may take home one or more packs of pills to start on the first day of the next menses, without returning.

Stricter conditions. For IUD insertion and sterilisation require the checklist, or a negative test with no unprotected sex in the last 3 weeks. For sterilisation confirm no pregnancy on the day.

Common errors.

• Relying on absence of menses as proof of non-pregnancy.

• Relying on a negative test within 3 weeks of unprotected sex.

• Refusing a method until menses return.

• Assuming lactational amenorrhoea protects after 6 months or when feeding is partial.

• Missing ectopic pregnancy in a patient with pain, previous ectopic pregnancy or tubal surgery.

Special groups. Adolescents with irregular cycles and women with amenorrhoea from other causes (hyperprolactinaemia, polycystic ovary syndrome, perimenopause) need a test rather than cycle-based reasoning. A patient with a late injection needs the checklist and a test when the late window has passed.

Referral and escalation. Refer urgently for a positive pregnancy test with pain, bleeding, an IUD in place or previous ectopic pregnancy. Give unintended pregnancy counselling covering all options and refer for safe abortion care where lawful.