<prompt> Contraceptive failure 10100 women years means:0.1 accidental pregnancy per 100 woman year using contraceptives100 accidental pregnancy per 1000 woman year using contraceptives10 accidental pregnancy per 1000 woman year using contraceptives10 accidental pregnancy per 100 woman year using contraceptives  <response>: D i.e. 10 accidental pregnancy per 100 woman year using contraceptivesRef: AH Suryakantha, Community Medicine with Recent Advances, 3rd edition, page 651Explanation:Named after Raymond PearlFailureRatePearlIndex TotalwomanmonthsofexposureTotalnumberofaccidentalpregnancies x1200A Pearl Index of 10 per HWY means that 10 out of 100 woman will become pregnant if they are using that particular method of contraception in one year.To interpret effectiveness of a contraceptive method a minimum of 600 months of exposure is usually considered as necessary.Other methods of evaluation are:Method failure.User failure.Life table analysis.Pearl Index of various contraceptives used are:Calendar Method -9100 HWY 9BBT Method -1-2100 HWY 1-2Cervical Mucus Method -3100 HWY 3Symptothermal Method -2100 HWY 2Foam Tablets - 0.5Condoms - 12Condoms correctly used - 3IUCD - 1-2OCP-0.1 