The Pearl Index is used to compare contraceptive efficacy. A contraceptive method with Pearl Index of 0.5 means:

• A 0.5% of women using this method become pregnant in one month
• B 99.5% of pregnancies are prevented with this method
• C The method fails in 0.5% of acts of intercourse
• D 0.5 pregnancies per 100 woman-years of use ✓

Explanation

Pearl Index = (Number of unintended pregnancies / Total months of exposure) × 1200, expressed as pregnancies per 100 woman-years. A Pearl Index of 0.5 means 0.5 pregnancies occur per 100 women using the method for one year — indicating high efficacy. Combined OCP has a Pearl Index of 0.1–0.5 (perfect use) vs 5–9 (typical use). Condoms have a Pearl Index of 2–15 (typical use). The Pearl Index is limited because it assumes constant failure rate over time, which is not always true.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.