Emergency contraception with levonorgestrel 1.5 mg (single dose) is most effective when taken within how many hours of unprotected intercourse?
- A 12 hours
- B 72 hours ✓
- C 24 hours
- D 120 hours
Correct answer: B. 72 hours
Explanation
Levonorgestrel emergency contraception (1.5 mg single dose or 0.75 mg × 2 doses 12 hours apart) is most effective when taken within 72 hours of unprotected intercourse, with efficacy decreasing over time (up to 95% if taken within 24 hours, ~85% within 72 hours). Ulipristal acetate can be used up to 120 hours. Copper-T IUD insertion within 5 days is the most effective 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.