A 24-year-old nulliparous woman presents 72 hours after unprotected intercourse with concerns about pregnancy. She weighs 78 kg, has no medical contraindications, and denies any history of pelvic inflammatory disease or STIs. She is unsure of her cycle dates. Which emergency contraceptive method should be avoided in this patient?

Explanation

## Emergency Contraception Selection in a 24-Year-Old Nulliparous Woman at 72 Hours **Key Point:** Levonorgestrel 1.5 mg has significantly **reduced efficacy in women weighing ≥75 kg** and should be avoided in this patient (78 kg). All other listed options remain effective regardless of body weight. ### Clinical Context Analysis This patient presents at **72 hours post-intercourse** with a body weight of **78 kg** — two critical factors that together determine the optimal emergency contraceptive (EC) choice: - **Weight ≥75 kg** is the primary concern: levonorgestrel efficacy is substantially reduced above this threshold - **72-hour window**: levonorgestrel is at its efficacy limit; ulipristal acetate and copper IUD remain highly effective - **Nulliparous status**: copper IUD insertion is technically feasible and not contraindicated - **No STI risk / no PID history**: copper IUD is safe to insert ### Emergency Contraceptive Options at 72 Hours | Method | Window | Efficacy in ≥75 kg Women | Notes | |--------|--------|--------------------------|-------| | **Copper IUD** | Up to 120 hrs | Unaffected (>99% effective) | Most effective EC; weight-independent | | **Ulipristal acetate 30 mg** | Up to 120 hrs | Maintained (superior to LNG) | SPRM; efficacy preserved in heavier women | | **Mifepristone 25 mg** | Up to 120 hrs | Maintained | Used as EC in some countries (China, Russia); progesterone antagonist | | **Levonorgestrel 1.5 mg** | Up to 72 hrs | **Significantly reduced** | EMA/WHO: reduced efficacy in women >75 kg; should be avoided | ### Why Levonorgestrel Should Be Avoided 1. **Weight-related reduced efficacy**: The European Medicines Agency (EMA) updated levonorgestrel labeling to warn that efficacy is reduced in women weighing >75 kg and may be completely lost above 80 kg. This patient at 78 kg falls squarely in this high-risk zone. 2. **At the 72-hour boundary**: Levonorgestrel efficacy declines sharply after 48–72 hours even in normal-weight women; combining this with weight >75 kg makes it the least appropriate choice. 3. **Superior alternatives are available**: Ulipristal acetate maintains efficacy up to 120 hours and is unaffected by body weight. The copper IUD is the most effective EC method regardless of weight. **High-Yield:** The WHO and EMA both recommend that women weighing ≥75 kg should be offered ulipristal acetate or a copper IUD in preference to levonorgestrel for emergency contraception. ### Why the Other Options Are Acceptable - **Ulipristal acetate (Option A)**: Selective progesterone receptor modulator; efficacy maintained up to 120 hours and unaffected by BMI/weight — **preferred oral EC** in this patient. - **Mifepristone 25 mg (Option B)**: Used as EC in several countries; acts as a progesterone antagonist to delay/inhibit ovulation; effective up to 120 hours and weight-independent. - **Copper IUD (Option D)**: Most effective EC (>99%); weight-independent; no contraindications in this patient (no active STI/PID, nulliparity alone is not a contraindication per WHO MEC Category 2). **Clinical Pearl:** When a patient weighs ≥75 kg and presents for emergency contraception, **levonorgestrel should be avoided** in favor of ulipristal acetate (oral) or copper IUD (most effective). This is a high-yield distinction for NEET PG / INI-CET. **Mnemonic:** **"Heavy patients need ULIPRISTAL or IUD"** — Levonorgestrel loses efficacy above 75 kg; ulipristal acetate and copper IUD do not. [cite: WHO Emergency Contraception Fact Sheet 2023; EMA Levonorgestrel Label Update 2014; Glasier A, Cameron ST et al., Lancet 2011; KD Tripathi Essentials of Medical Pharmacology 9e]