A 32-year-old breastfeeding woman comes to the clinic 36 hours after unprotected intercourse. She is exclusively breastfeeding her 2-month-old infant. Which emergency contraceptive is the safest choice in this scenario?

Explanation

## Emergency Contraception in Breastfeeding: Copper IUD as Preferred Option ### Clinical Context When a breastfeeding woman requires emergency contraception, hormonal methods pose a theoretical risk of infant exposure through breast milk. This fundamentally changes the drug-of-choice algorithm. ### Why Hormonal Methods Are Avoided in Breastfeeding **Key Point:** Levonorgestrel, mifepristone, and ulipristal acetate are all excreted in breast milk to varying degrees. Although the absolute amount reaching the infant is small, WHO and most guidelines recommend avoiding these agents in exclusively breastfeeding women, particularly in the first 6 months of life when the infant's detoxification capacity is immature. - **Levonorgestrel:** Excreted in breast milk; relative infant dose ~0.1% of maternal dose (low but not negligible) - **Mifepristone:** Excreted in breast milk; limited safety data in breastfeeding - **Ulipristal acetate:** Excreted in breast milk; insufficient safety data in breastfeeding ### Copper IUD: The Safest Choice **High-Yield:** Copper IUD is the **safest and most effective** emergency contraceptive in breastfeeding women because: 1. **No systemic absorption:** Copper IUD acts locally in the uterus; no hormone enters breast milk 2. **Highest efficacy:** >99% effective; superior to all hormonal methods 3. **Extended window:** Can be inserted up to 5 days post-intercourse (120 hours) 4. **Dual benefit:** Provides long-term contraception (3–10 years depending on device) 5. **Breastfeeding-compatible:** WHO Category 1 (no restrictions) ### Comparison: Emergency Contraception in Breastfeeding | Method | Breast Milk Excretion | WHO Category | Efficacy | Feasibility | |--------|----------------------|--------------|----------|-------------| | **Copper IUD** | None (local action) | Category 1 | >99% | Requires insertion; most effective | | Levonorgestrel | Yes (~0.1% infant dose) | Category 2 | ~60% | Accessible but not ideal | | Mifepristone | Yes (limited data) | Category 3 | ~85% | Not recommended in breastfeeding | | Ulipristal acetate | Yes (limited data) | Category 3 | ~85% | Not recommended in breastfeeding | **WHO Category 1:** Method can be used without restriction; Category 2: Benefits outweigh risks; Category 3: Risks outweigh benefits. ### Clinical Pearl **Clinical Pearl:** If the breastfeeding woman is not a candidate for IUD insertion (e.g., anatomical contraindication, patient refusal), levonorgestrel can be used as a compromise, with counseling about minimal but theoretical infant exposure. However, copper IUD remains the gold standard. ### Practical Considerations **Tip:** In a breastfeeding woman presenting 36 hours post-intercourse: - **First choice:** Copper IUD insertion (if trained provider available) - **Second choice:** Levonorgestrel (if IUD not feasible; discuss risks) - **Avoid:** Mifepristone and ulipristal acetate (insufficient safety data) **Warning:** Do not delay emergency contraception while awaiting IUD insertion if the window is closing. Levonorgestrel is acceptable if IUD is not immediately available. [cite:Park 26e Ch 8; WHO Medical Eligibility Criteria for Contraceptive Use]