Pearls index
Pearl index is defined as the number of failures per 100 woman years of exposure (HWY) Failure rate per Hundred Women Years = Total accidental pregnancies X 1200/ Total months of exposure Reference : Park&;s textbook of preventive and social medicine, 23rd edition, Page no: 510
Per 10 woman years
Per 100 woman years
Per 1000 woman years
Per 10,000 woman years
Demography and family planning