Charlotte Ellertson

New estimates of the effectiveness of the Yuzpe regimen of emergency contraception

The purpose of this study was to provide new estimates of the effectiveness of the Yuzpe method of emergency contraception and to offer correctly computed estimates of the confidence intervals for estimated effectiveness rates. Through a literature search, seven studies that present the number of women treated and outcome of treatment by cycle day of unprotected intercourse relative to expected day of ovulation were identified. Probabilities of conception by cycle day of intercourse among women not using contraception and the associated variance-covariance matrix from five other datasets were estimated, and these external estimates were used to assess the effectiveness of the Yuzpe regimen. The 40 estimates of effectiveness, based on seven separate studies and the seven studies combined and five different sets of conception probabilities by cycle day, ranged from a low of 44.2% to a high of 88.7%. The preferred point estimate is that emergency contraceptive pills reduce the risk of pregnancy by 75.4%, with a 95% confidence interval extending from 65.6% to 82.4%. True effectiveness is likely to be at least 75% because treatment failures (observed pregnancies) include women who were already pregnant when treated and women who became pregnant after being treated.

Safety, efficacy, and acceptability of medical abortion in China, Cuba, and India: A comparative trial of mifepristone-misoprostol versus surgical abortion

OBJECTIVE We investigated safety, efficacy, and acceptability of an oral regimen of medical abortion compared with surgical abortion in three developing countries. STUDY DESIGN Women (n = 1373) with amenorrhea < or = 56 days chose either surgical abortion (as provided routinely) or 600 mg of mifepristone followed after 48 hours by 400 micrograms of misoprostol. This is the appropriate design for studying safety, efficacy, and acceptability among women selecting medical abortion over available surgical services. RESULTS The medical regimen had more side effects, particularly bleeding, than did surgical abortion but very few serious side effects. Failure rates for medical abortion, although low, exceeded those for surgical abortion: 8.6% versus 0.4% (China), 16.0% versus 4.0% (Cuba), and 5.2% versus 0% (India). Nearly half of failures among medical clients were not true drug failures, however, but surgical interventions not medically necessary (acceptability failures or misdiagnoses). Women were satisfied with either method, but more preferred medical abortion. CONCLUSION Medical abortion can be safe, efficacious, and acceptable in developing countries.

The effectiveness of the Yuzpe regimen of emergency contraception.

A review of the 10 clinical trials of the Yuzpe method of emergency contraception that reported the data required to calculate effectiveness rates suggests that this may be a more accurate measure of efficacy than the failure rate. The Yuzpe regimen, which involves the administration of 200 mcg of ethinyl estradiol and 2.0 mg of norgestrel, was associated with failure rates ranging from 0.2% to 2.8%; the pooled rate was 1.5% (95% exact confidence interval, 1.2-1.9%). The equality of failure rates across studies was compromised by two assumptions: women lost to follow-up (as high as 22%) became pregnant at the same rate as women observed, and all women in the trials had an equal probability of failure. The effectiveness rate--the proportionate reduction in the probability of conception caused by emergency contraception use--avoids these sources of error by including data on both the observed and expected number of pregnancies and computing the risk of conception for each day of the menstrual cycle. These estimates range from 55.3% to 94.2%, with a pooled effectiveness rate of 74.0% (95% exact confidence interval, 68.2-79.3%). On the other hand, four methodological issues are inherent in use of the effectiveness rate: the assumption of homogeneity implicit in pooling observations, bias introduced by the unknown pregnancy rate among women lost to follow-up, the probability some women violated study protocol and had more than one unprotected act of intercourse during their cycle, and possible underestimation of the expected number of pregnancies.

Preventing unintended pregnancy: the cost-effectiveness of three methods of emergency contraception.

OBJECTIVES This study examined the cost-effectiveness of emergency contraceptive pills, minipills, and the copper-T intrauterine device (IUD) as emergency contraception. METHODS Cost savings were modeled for both (1) a single contraceptive treatment following unprotected intercourse and (2) emergency contraceptive pills provided in advance. RESULTS In a managed care (public payer) setting, a single treatment of emergency contraception after unprotected intercourse saves

Emergency contraception: randomized comparison of advance provision and information only.

142 (

Extending the time limit for starting the Yuzpe regimen of emergency contraception to 120 hours.

54) with emergency contraceptive pills and

Estimating the effectiveness of emergency contraceptive pills.

119 (

Emergency contraception: a review of the programmatic and social science literature

29) with minipills. The copper-T IUD is not cost-effective as an emergency contraceptive alone, but savings quickly accrue as use continues. Advance provision of emergency contraceptive pills to women using barrier contraceptives, spermicides, withdrawal, or periodic abstinence saves from

The emergency contraceptive pill: a survey of knowledge and attitudes among students at Princeton University.

263 to

Can women in less-developed countries use a simplified medical abortion regimen?

498 (