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the number of failures of a contraceptive method per 100 woman years of exposure.
Pearl IndexObstetrics A formula that allows comparison of the efficacy of contraceptive methods, calculated as the pregnancy rate in population divided by 100 yrs of exposure. See Breast feeding, Coitus interruptus, Condoms, Morning-after pill, Contraception, Natural family planning, Norplant, Rhythm method, RU 486.
Pearl index–pregnancies/100 years of use
Physiologic 15-30/100 years: Coitus interruptus, natural family planning (rhythm or safe period), eg calendar method, evaluation of cervical mucosa or temperature, breast feeding
Chemical 15-20/100 years: Contraceptive sponges
Barrier 2-20/100 years: Intrauterine devices, condoms
Hormonal 1-3/100 years
Surgical << 1/100 years: Ligation of fallopian tubes, vas deferens
Pearl in·dex(pĕrl in'deks)
The number of failures of a contraceptive method per 100 woman years of exposure.
Pearl,Raymond, U.S. biologist, 1879-1940.
Pearl index - the number of failures of a contraceptive method per 100 woman years of exposure.