Before revision: Calculation Three kinds of information are needed to calculate a Pearl Index for a particular study: the total number months or cycles of exposure by women in the study the number of pregnancies the reason for leaving the study (pregnancy or other reason) the number of children in a single pregnancy (twins or triplets can affect the final number) There are two calculation methods for determining the Pearl Index: in the first method, the relative number of pregnancies in the study is divided by the number of months of exposure, and then multiplied by 1200 in the second method, the number of pregnancies in the study is divided by the number of menstrual cycles experienced by women in the study, and then multiplied by 1300.
After revision: Calculation Several kinds of information are needed to calculate a Pearl Index for a particular study: the total number months or cycles of exposure by women in the study the number of pregnancies the reason for leaving the study (pregnancy or other reason) the number of children in a single pregnancy (twins or triplets can affect the final number) There are two calculation methods for determining the Pearl Index: in the first method, the relative number of pregnancies in the study is divided by the number of months of exposure, and then multiplied by 1200 in the second method, the number of pregnancies in the study is divided by the number of menstrual cycles experienced by women in the study, and then multiplied by 1300.