Missed Period After Emergency Contraception: Pregnancy Still Possible?

Emergency contraceptive pills (ECPs: levonorgestrel 1.5 mg or ulipristal acetate 30 mg) delay ovulation – they do not disrupt established pregnancy.

Effects on Menstrual Cycle

• Period may come earlier, later, heavier, lighter, or with spotting.
• Delay up to 1 week common; >1 week late → test for pregnancy.
• Cycle irregularity can persist 1–2 cycles.

Pregnancy Risk After ECP

• Levonorgestrel: ~1–2% failure (higher if >72 hrs, BMI >25, near ovulation).
• Ulipristal: ~1% failure (effective up to 120 hrs, less BMI effect).
• If ovulation already occurred, ECP ineffective.

Testing Strategy

1. If period >7 days late: urine hCG test (first-morning urine).
2. If negative but no period in another week: repeat test or serum quantitative hCG.
3. If positive: confirm with clinician (viability, location – ectopic risk unchanged).

Important Notes

• ECP is not abortifacient; no effect on implanted embryo.
• Start regular contraception immediately (ECP not for ongoing use).
• Copper IUD as ECP: >99% effective up to 5 days post-coitus; provides ongoing contraception.

When in doubt, test. Early prenatal care or timely decision-making requires confirmation.