Skjeldestad F E
Department of Gynecology and Obstetrics, University Hospital of Trondheim, Norway.
Fam Plann Perspect. 1995 Mar-Apr;27(2):71-3, 96.
Data from a 1989-1990 case-control study of contraceptive efficacy in Norway compare contraceptive use among women who requested an abortion (1,386 cases) with women who responded to a general fertility survey (2,627 controls). In a logistic regression analysis measuring contraceptive efficacy as the odds of avoiding a pregnancy that terminated in an induced abortion compared with the odds for nonuse, consistent condom use was found to lower fecundity by 88.9%, diaphragm use by 89.3%, the pill by 97.8%, the IUD by 97.6%, vasectomy by 99.5%, and female sterilization by 99.8%. The relative contraceptive efficacy of the condom, the IUD and the pill did not vary by marital status or parity but did vary with age; the proportion by which each of these methods reduced fecundity declined among successively older age-groups.
1989 - 1990年挪威一项关于避孕效果的病例对照研究数据，将要求堕胎的女性（1386例）的避孕措施使用情况与一般生育调查的女性（2627例对照）进行了比较。在一项逻辑回归分析中，将避孕效果衡量为与未使用避孕措施相比避免因人工流产而终止妊娠的几率，结果发现持续使用避孕套可使生育力降低88.9%，使用子宫帽降低89.3%，使用避孕药降低97.8%，使用宫内节育器降低97.6%，男性绝育降低99.5%，女性绝育降低99.8%。避孕套、宫内节育器和避孕药的相对避孕效果不因婚姻状况或生育次数而有所不同，但会随年龄变化；这些方法中每种方法降低生育力的比例在年龄较大的年龄组中依次下降。
