What is the Yuzpe method of emergency contraception, including dosing schedule, contraindications, side effects, and alternative options?

Yuzpe Method of Emergency Contraception

The Yuzpe method is a combined estrogen-progestin emergency contraceptive regimen that is now considered a second-line option due to lower efficacy and higher side effects compared to levonorgestrel or ulipristal acetate, but remains useful when dedicated emergency contraceptive pills are unavailable. 1

What It Is

The Yuzpe method consists of using regular combined oral contraceptive pills in high doses as emergency contraception. The regimen involves:

• First dose: 100 μg ethinyl estradiol + 0.50 mg levonorgestrel
• Second dose: Same dosing repeated 12 hours later 1

This can be achieved using various brands of combined oral contraceptives (except triphasic pills), making it accessible when dedicated emergency contraceptive products are not available 2.

Dosing Schedule

• Take the first dose as soon as possible within 72 hours (3 days) of unprotected intercourse 1
• Take the second dose exactly 12 hours after the first dose 1, 3
• Timing matters: Efficacy decreases as the interval between intercourse and treatment increases, with effectiveness declining significantly after 72 hours 4

Efficacy

The Yuzpe method prevents approximately 74-75% of expected pregnancies when used correctly 5, 4. This makes it:

• Less effective than levonorgestrel (which prevents ~85% of pregnancies) 6, 4
• Less effective than ulipristal acetate (which prevents ~85% of pregnancies and works better 3-5 days post-intercourse) 1
• Much less effective than the copper IUD (which prevents >90% of pregnancies) 4

Research shows that a single dose may be nearly as effective as the two-dose regimen (2.9% vs 2.0% failure rate), though the standard remains two doses 3.

Side Effects

The Yuzpe method has significantly more side effects than other emergency contraceptive options 1:

• Nausea: Affects approximately 50% of users 6
• Vomiting: Occurs in about 20% of users 6
• Other common effects: menstrual disturbances, breast tenderness, abdominal cramping, dizziness, headache, mood changes 5

Important caveat: Taking the pills with food does NOT reduce nausea or vomiting 3. Consider prophylactic meclizine to reduce gastrointestinal symptoms 6.

If vomiting occurs within 3 hours of taking a dose, that dose should be repeated 1.

Contraindications

The Yuzpe method has no absolute medical contraindications for emergency use 6. Key points:

• Not indicated if pregnancy is already confirmed, but will not harm an existing pregnancy if inadvertently taken 6
• The same contraindications that apply to ongoing combined oral contraceptive use technically apply, but the short-term nature of emergency contraception makes the risk-benefit ratio favorable in most situations 5
• Does not protect against sexually transmitted infections

Alternative Options (In Order of Preference)

Based on the evidence prioritizing efficacy and tolerability:

1. Copper IUD (Most Effective)

• Can be inserted within 5 days of unprotected intercourse (or up to 5 days after ovulation if timing is known) 1
• Prevents >90% of pregnancies 4
• Provides ongoing contraception
• Limitation: Requires trained provider and infrastructure; not suitable for women at risk of STIs 2

2. Ulipristal Acetate (30 mg single dose)

• More effective than levonorgestrel 3-5 days after intercourse 1
• Works better in obese women compared to levonorgestrel 1, 2
• Effective up to 120 hours (5 days) with consistent efficacy 1
• Fewer side effects than Yuzpe 2

3. Levonorgestrel (1.5 mg single dose or 0.75 mg × 2 doses)

• Prevents ~85% of pregnancies 6, 4
• Much better tolerated than Yuzpe with significantly less nausea and vomiting 6
• Can be taken as single 1.5 mg dose (more convenient) 1
• Efficacy declines after 72 hours 2
• May be less effective in obese women 1

4. Yuzpe Method (Last Resort)

• Use only when dedicated emergency contraceptive methods are unavailable 2
• Any combined oral contraceptive can be used (except triphasic formulations) 2

Clinical Algorithm for Emergency Contraception Selection

Within 72 hours of unprotected intercourse:

• First choice: Copper IUD (if patient appropriate and resources available)
• Second choice: Levonorgestrel (readily available, well-tolerated)
• If obese: Prefer ulipristal acetate or copper IUD over levonorgestrel 1

72-120 hours after unprotected intercourse:

• First choice: Copper IUD
• Second choice: Ulipristal acetate (maintains efficacy better than levonorgestrel) 1

When dedicated products unavailable:

• Use Yuzpe method with any available combined oral contraceptive 2

Important Clinical Pearls

• Advance provision of emergency contraceptives increases use but has not been shown to reduce unintended pregnancy rates at 12 months 1
• Starting sooner does NOT appear to improve efficacy within the 72-hour window for the Yuzpe method 3
• Women can start any regular contraceptive method immediately after using emergency contraception 1
• The second dose of Yuzpe can be eliminated if tolerability is a major concern, with only modest reduction in efficacy 3