What are the available emergency contraceptive options?

Emergency Contraceptive Options

Ulipristal acetate (Ella) is the most effective emergency contraception option, preventing approximately 85% of expected pregnancies when taken within 120 hours (5 days) after unprotected intercourse, and is superior to levonorgestrel, especially for women who are overweight or obese. 1

Available Emergency Contraceptive Options

1. Ulipristal Acetate (Ella)

• Effectiveness: Prevents approximately 85% of expected pregnancies 1
• Timeframe: Effective up to 120 hours (5 days) after unprotected intercourse 1, 2
• Mechanism: Progesterone receptor modulator that delays or inhibits ovulation even when taken 24-48 hours before expected ovulation 3
• Access: Requires a prescription 1
• Dosage: Single 30 mg oral tablet 2
• Key advantages:
  • More effective than levonorgestrel between days 3-5 after unprotected intercourse 1
  • 42% lower pregnancy risk than levonorgestrel up to 72 hours, and 65% lower in the first 24 hours 3
  • Effective even close to ovulation when levonorgestrel is no longer effective 3

2. Levonorgestrel (Plan B)

• Effectiveness: Prevents approximately 75-80% of expected pregnancies 1
• Timeframe: Most effective within 72 hours (3 days) after unprotected intercourse 1
• Access: Available over-the-counter for all ages 1
• Dosage: Single 1.5 mg dose 4
• Key consideration: Less effective than ulipristal acetate, particularly after 72 hours and in women who are overweight or obese 1, 5

3. Copper IUD (Not detailed in evidence but important to include)

• Can be placed up to 5 days after unprotected intercourse
• Most effective emergency contraception option (>99% effective)
• Provides ongoing contraception for up to 10 years

Important Clinical Considerations

Timing of Administration

• All emergency contraception should be initiated as soon as possible after unprotected intercourse 1
• The CDC supports advance provision of emergency contraceptive pills 1
• If vomiting occurs within 3 hours of taking ulipristal acetate, consider repeating the dose 2

After Using Emergency Contraception

• After ulipristal acetate use:
  • Wait at least 5 days before starting hormonal contraception 1, 2
  • Use a reliable barrier method until the next menstrual period 2
• Rapid return of fertility is likely after emergency contraception use 2
• Emergency contraception may alter the next expected menstrual period 2
  • If menses is delayed beyond 1 week, rule out pregnancy 2

Common Side Effects

• Most frequent adverse events with ulipristal acetate: headache (18%), abdominal pain (12%), nausea (12%), dysmenorrhea (9%), fatigue (6%), and dizziness (5%) 2
• Similar side effect profile for levonorgestrel 6

Important Warnings

• Emergency contraception does not protect against sexually transmitted infections 2
• Not intended for routine use as a contraceptive 2
• Contraindicated in known or suspected pregnancy 2
• Evaluate women who become pregnant or complain of lower abdominal pain after taking emergency contraception for ectopic pregnancy 2

Drug Interactions

• Drugs or herbal products that induce CYP3A4 may decrease the effectiveness of ulipristal acetate 2
• Initiation of progestin-containing contraceptives may impair the ability of ulipristal acetate to delay ovulation 2

Cost-Effectiveness

Ulipristal acetate is cost-effective compared to levonorgestrel when considering the costs of unintended pregnancy, with an incremental cost-effectiveness ratio of £311 per prevented pregnancy 7.