Contraceptive Failure Rate Analysis

This question assesses the understanding of failure rates for various contraceptive methods, measured per 100 Women Years (HWY).

Method Failure Rate Evaluation

Let's evaluate each statement based on typical failure rates:

• Statement 1: Depot medroxyprogesterone acetate (DMPA) 0-1 per HWY
  DMPA (the "shot") has a typical-use failure rate of about $0.3\%$ or $0.3$ per HWY. The range $0-1$ per HWY is consistent with its effectiveness. Thus, statement 1 is considered correct.
• Statement 2: Norplant 0-1 per HWY
  Norplant (now replaced by other implants like Jadelle) has a very low typical-use failure rate, around $0.05\%$ to $0.15\%$. The range $0-1$ per HWY is a reasonable representation. Thus, statement 2 is considered correct.
• Statement 3: LNG-IUS 0.02 per HWY
  Levonorgestrel-releasing intrauterine systems (LNG-IUS, e.g., Mirena) are highly effective, with typical and perfect-use failure rates around $0.1\%$ to $0.2\%$. A value of $0.02$ per HWY represents an extremely low failure rate, accurately reflecting its high efficacy, possibly representing perfect use or a specific model. Thus, statement 3 is considered correct.
• Statement 4: Levonorgestrel 3 per HWY
  This likely refers to oral contraceptive pills containing levonorgestrel. Typical-use failure rates for oral contraceptives (combined or progestin-only) are significantly higher, around $7-9$ per HWY. Even perfect-use failure rates are generally lower than $3$ per HWY for most formulations. Therefore, $3$ per HWY is comparatively high and considered incorrect in the context of highly effective methods listed.

Selecting the Correct Combination

Based on the analysis, statements 1, 2, and 3 are considered correct regarding the low failure rates of DMPA, Norplant, and LNG-IUS.

Therefore, the correct option is the one including statements 1, 2, and 3.