A 24-year-old nurse requests emergency contraception 36 hours after unprotected intercourse. She has no contraindications to any method. Which emergency contraceptive has the highest efficacy at this interval?

• A Copper IUD insertion within 5 days ✓
• B Levonorgestrel 1.5 mg orally as a single dose
• C Ulipristal acetate 30 mg orally as a single dose
• D Combined oral contraceptive pill (Yuzpe regimen)

Explanation

Copper IUD insertion within 120 hours (5 days) of unprotected intercourse is the most effective emergency contraceptive method, with failure rates <0.1%. It is also the only EC method that provides ongoing contraception. At 36 hours, ulipristal acetate is more effective than levonorgestrel among oral methods (maintains efficacy up to 120 hours vs levonorgestrel's declining efficacy beyond 72 hours), but copper IUD remains the gold standard for immediate efficacy.

Reference: Shaw's Textbook of Gynaecology, 17th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.