Which feature best distinguishes the contraceptive efficacy of copper-containing intrauterine devices (Cu-IUD) from levonorgestrel-releasing intrauterine systems (LNG-IUS) in Indian women?

Explanation

## Distinguishing Cu-IUD from LNG-IUS ### Efficacy and Mechanism Comparison | Feature | Cu-IUD | LNG-IUS | |---------|--------|----------| | **Pearl Index (failures/100 woman-years)** | 0.8 | 0.2 | | **Duration of effectiveness** | 10 years | 5–7 years | | **Menstrual bleeding pattern** | Increased (20–30% heavier) | Reduced/amenorrhea (30–40%) | | **Mechanism** | Copper toxicity + inflammatory response | Progestin-induced endometrial atrophy | | **Expulsion rate** | 3–5% | <2% | | **Systemic hormone absorption** | None | Minimal (mostly local) | ### Key Point: **LNG-IUS provides superior menstrual bleeding control and lower expulsion rates**, making it the best discriminator. While both are highly effective, the LNG-IUS's progestin-induced endometrial changes reduce bleeding (often to amenorrhea), whereas Cu-IUD typically increases menstrual flow by 20–30%. ### High-Yield: LNG-IUS is preferred in women with: - Heavy or prolonged menstrual bleeding - Dysmenorrhea (progestin provides pain relief). Cu-IUD is preferred in women who: - Wish to avoid hormonal methods. - Have contraindications to progestins (e.g., history of breast cancer). ### Clinical Pearl: The lower expulsion rate of LNG-IUS (due to its larger, more stable frame and progestin-induced endometrial fibrosis) is a major advantage in nulliparous women, contrary to older teaching. Both are now first-line in nulliparous women in developed guidelines. ### Warning: ~~Cu-IUD is contraindicated in nulliparous women~~ — this is outdated. Current NEET PG / WHO guidelines recommend IUDs (both Cu and LNG) as first-line in all women, including nulliparous and adolescents, when infection risk is low. [cite:Park 26e Ch 6]