Which emergency contraceptive method remains effective up to five days after unprotected intercourse?

Emergency Contraception Effective Up to 5 Days After Unprotected Sex

Both ulipristal acetate (UPA/Ella) and the copper IUD remain effective up to 5 days (120 hours) after unprotected intercourse, with the copper IUD being the most effective option overall. 1

Primary Options at 5 Days Post-Intercourse

Copper IUD (Most Effective)

• Can be inserted within 5 days of unprotected intercourse 1
• Highly effective as emergency contraception and provides the added benefit of ongoing long-term contraception 1
• Can even be inserted beyond 5 days if the day of ovulation can be estimated, as long as insertion occurs within 5 days after ovulation 1

Ulipristal Acetate (UPA/Ella) - Oral Option

• Single 30 mg dose effective within 120 hours (5 days) 1
• Superior efficacy compared to levonorgestrel between 72-120 hours after unprotected intercourse 1
• Studies show consistent pregnancy prevention when administered within 120 hours, with efficacy that does not decrease significantly over the 5-day window 1, 2
• More effective than levonorgestrel in obese women 1

Why Levonorgestrel (Plan B) Is NOT the Answer Here

While levonorgestrel can technically be taken up to 5 days after intercourse, its efficacy declines significantly after 72 hours 1. The CDC guidelines specifically note that pregnancy rates increase at 4-5 days with levonorgestrel 1. A meta-analysis found pregnancy rates were low within 4 days but increased at 4-5 days 1.

Comparative Effectiveness at Days 3-5

UPA demonstrates superior effectiveness to levonorgestrel in the 72-120 hour window:

• Between 72-120 hours: UPA prevented significantly more pregnancies than levonorgestrel (0 pregnancies vs 3 pregnancies, p=0.037) 2
• UPA efficacy remains stable across the entire 120-hour period, with pregnancy rates of 2.3% at >48-72 hours, 2.1% at >72-96 hours, and 1.3% at >96-120 hours 2

Clinical Decision Algorithm

At 5 days (120 hours) post-intercourse:

1. First choice: Copper IUD - if patient is appropriate candidate (no contraindications, trained provider available, not at high risk for STIs)

   • Provides most effective emergency contraception
   • Offers continued contraception

2. Second choice: Ulipristal acetate 30 mg - if IUD not feasible or desired

   • Requires prescription
   • Take as single dose immediately
   • After taking UPA, abstain from sex or use barrier contraception for 14 days or until next menses 1

3. Avoid levonorgestrel at this timepoint - efficacy significantly reduced after 72 hours

Important Caveats

• Timing is critical: Even with methods effective up to 5 days, earlier administration is always better 3, 4
• UPA and hormonal contraception: After UPA use, regular hormonal contraception can be started immediately, but backup barrier contraception is needed for 14 days 1
• Pregnancy testing: Advise pregnancy test if withdrawal bleeding doesn't occur within 3 weeks 1
• The 2015 CDC guidelines emphasize that UPA may be more effective than levonorgestrel after the first 72 hours 5