A 28-year-old woman takes emergency contraception (levonorgestrel 1.5 mg) 60 hours after unprotected intercourse. According to clinical evidence, the likely efficacy (reduction in pregnancies compared to expected without treatment) is approximately:
- A 58% ✓
- B 90%
- C 75%
- D 99%
Correct answer: A. 58%
Explanation
Levonorgestrel ECP efficacy decreases with time: within 24h ~95% reduction, 24–48h ~85%, 48–72h ~58% reduction in expected pregnancies. It primarily acts by delaying or inhibiting ovulation and is ineffective after ovulation. This information aids counselling — earlier use is strongly preferred. The copper IUD, inserted within 5 days, provides >99% efficacy as emergency contraception.
Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.