Contraceptive efficacy expressed as: (A) 100 women months, (B) 1000 women years, (C) 100 women years, (D) 10 women years
Answer is C. Contraceptive efficacy is assessed by measuring the number of unplanned pregnancies that occur during a specified period of exposure and use of contraceptive methods.Contraceptive efficacy is measured using Pearl index and life table analysis. Pearl index is number of failure per 100 woman-years of exposure (HWY) HWY=total accidental pregnancies/total months of exposure.*1200 Life table analysis measure failure rate per month of exposure. Park&;s textbook of preventive and social medicine.K Park. Edition 23.Pg no: 510