A contraceptive "X" is used by 100 couples for continuous period of 2 years. During this period 20 women become pregnant despite using contraceptive "X". What is the pearl index of contraceptive "X"?
High-Yield Explanation
- The Pearl index is defined as the number of "failures per 100 woman-years of exposure (HWY)." - This rate is given by the formula : - PI = Total accidental pregnancies x 1200/ Total months of exposure In given question: Total accidental pregnancies=20 Total months of exposure=100 couples x 24 months each=2400 months PI = 20 x1200/ 2400 =10 per HWY