Pills or placebos?
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Biomedical subjects
Publications and source records attributed to J Trussell.
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The purpose of this study was to provide revised estimates of the effectiveness of the Yuzpe method of emergency contraception. Through a literature search, we identified eight studies that present the number of women treated and outcome of treatment by cycle day of unprotected intercourse relative to expected day of ovulation. Using five sets of external estimates of conception probabilities by cycle day of intercourse among women not using contraception, we assessed the effectiveness of the Yuzpe regimen. The 45 estimates of effectiveness, based on eight separate studies and the eight studies combined and five different sets of conception probabilities by cycle day, ranged from a low of 56.4% to a high of 89.3%. Our preferred point estimate is that the Yuzpe regimen reduces the risk of pregnancy by 74.1%, with a 95% confidence interval extending from 62.9% to 79.2%. True effectiveness is likely to be > 74% because treatment failures (observed pregnancies) include women who were already pregnant when treated and women who became pregnant after being treated.
OBJECTIVE: To determine risk factors for pregnancy after tubal sterilization with bipolar electrocoagulation. METHODS: A total of 2267 women who had bipolar electrocoagulation were followed for up to 8 to 14 years as part of a multicenter, prospective, cohort study conducted in medical centers in nine United States cities. We used proportional hazards analysis and cumulative life-table probabilities to assess pregnancy risk in these women. RESULTS: The 5-year cumulative probability of pregnancy for women sterilized in 1978-1982 was 19.5 per 1000 procedures (95% confidence interval [CI], 12.2, 26.9); the comparable probability for women sterilized in 1985-1987 was significantly lower, 6.3 per 1000 procedures (95% CI, 0.0, 13.5) (one-tailed P = .01). Women enrolled in 1985-1987 who had fewer than three sites of coagulation had a probability of failure of 12.9 per 1000 procedures (95% CI, 0.0, 38.0); by contrast, women who had three or more sites coagulated had a probability of failure of 3.2 per 1000 procedures (95% CI, 0.0, 9.6) (one-tailed P = .01). CONCLUSION: The long-term probability of pregnancy after tubal sterilization with bipolar coagulation was very low when three or more sites of the fallopian tube were coagulated. Bipolar coagulating systems can be highly effective for sterilization when the fallopian tube is coagulated adequately.
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OBJECTIVES: We hypothesized that movement from traditional indemnity insurance to managed care in California between 1983 and 1994 would lead to reductions in the rate of cesarean delivery. STUDY DESIGN: We decomposed the frequency of cesarean delivery with each primary diagnosis into the product of the diagnosis rate among all women and the cesarean delivery rate among women with the given diagnosis (conditional cesarean delivery rate). We used logistic regression to estimate the diagnosis and conditional cesarean delivery rates. RESULTS: Adjusted and observed cesarean delivery rates are indistinguishable. Both the diagnosis rates and the conditional cesarean delivery rates contributed to the increase in the cesarean delivery rate between 1983 and 1987. The subsequent decline is attributable to the decline in the repeated cesarean delivery rate. CONCLUSIONS: The increase in managed care in California played no apparent role in the decline in the cesarean delivery rate. With the exception of Kaiser health maintenance organizations, managed care providers and indemnity insurers managed deliveries similarly.
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.
No investigator has attempted to measure prospectively the true efficacy of a contraceptive method, compared with a control group using no method, because contraceptive trials focus on women trying to avoid pregnancy and ethical concerns do not permit the withholding of contraception. We tested the feasibility of an approach that recruited women who desired pregnancy but were willing to postpone conception by 1 month. In this protocol, we restricted frequency and timing of intercourse to one coital act on the most fertile day of the menstrual cycle, as measured by a luteinizing hormone (LH) detection kit. Participants were randomized to use either a male latex condom, spermicidal film, or no method. In this feasibility study we recruited 58 women at three sites, with one site recruiting 25 women in 5 months. Among 54 women who completed the study, we found a 12% pregnancy rate for the group using no method (2/17; 95% confidence interval [CI], 1-36%) and an 11% pregnancy rate for the group using spermicidal film (2/18; 95% CI, 1-35%). No pregnancies occurred among the 19 women using condoms (0/19; 95% CI, 0-18%). The wide confidence intervals illustrate the small sample size of this pilot study and no conclusions can be drawn about the relative efficacy of the methods. Having demonstrated the feasibility of this study design, we now urge the initiation of a large-scale study to evaluate the efficacy of barrier methods using our randomized approach, with a control arm using no method of contraception.
The availability of emergency contraception (EC) introduces new complexities to barrier contraceptive evaluation. Researchers must determine whether the primary objective of interest is to measure the effectiveness of the barrier plus EC back-up or the effectiveness of the barrier alone. Barrier contraceptive effectiveness study protocols must specify what study volunteers will be told about EC, under what conditions EC will be dispensed, what information about EC use will be collected, and how EC use will be addressed during data analysis.
Leading health agencies, including the World Health Organization and the US Food and Drug Administration, consider emergency contraceptive pills (ECPs) safe and effective and have called for better access to them. Yet debate about whether ECPs should continue to be available by prescription only has been limited. After measuring the characteristics of ECPs against criteria developed to assess the necessity for prescription status for drugs generally, we argue that ECPs can safely be marketed over the counter. Professional assistance is not necessary since the woman diagnoses her own need for the pills and takes them herself. ECPs do not need to be adjusted for the individual woman and pose no potential threat of overdose or addiction. There are no contraindications except confirmed pregnancy (in which case the therapy will not work), and monitoring is not necessary. We conclude that prescription requirements that keep ECPs from women provide little, if any, benefit.
In 1997, the nonprofit Reproductive Health Technologies Project and the Office of Population Research at Princeton University, together with the communications firm Elgin DDB, planned and executed a mass media campaign to advertise the Emergency Contraception Hotline and more generally to further awareness of emergency contraception as a last chance means of pregnancy prevention in the United State. We produced a variety of public service announcements (PSAs) including television and radio spots in English and Spanish and several print versions adaptable for newspapers and magazines as well as outdoor settings such as billboards, transit shelters, and the sides of buses. Working with local coalitions, we succeeded in placing the PSAs free of charge in six pilot cities. We also generated coverage about the campaign in local and national news outlets. We chronicle the development of the media campaign, discuss the challenges and obstacles faced, and conclude with a review of the principal lessons learned.
BACKGROUND: Tubal sterilization is an increasingly common method of contraception in the United States. Although pregnancy after sterilization is uncommon, it can occur and may be ectopic. We used data from the U.S. Collaborative Review of Sterilization to estimate the risk of ectopic pregnancy in women who had undergone the common types of tubal sterilization. METHODS: A total of 10,685 women undergoing tubal sterilization were followed in a multicenter, prospective cohort study. We intended to follow all the women for 5 years by means of annual telephone interviews; for women enrolled early in the study, we attempted an additional follow-up telephone interview 8 to 14 years after sterilization. To assess the risk of ectopic pregnancy in these women, we used cumulative life-table probabilities and proportional-hazards analysis. RESULTS: There were 47 ectopic pregnancies in the 10,685 women; the 10-year cumulative probability of ectopic pregnancy for all methods of tubal sterilization combined was 7.3 per 1000 procedures. The cumulative probability varied substantially according to the method of sterilization and the woman's age at the time of sterilization. Women sterilized by bipolar tubal coagulation before the age of 30 years had a probability of ectopic pregnancy that was 27 times as high as that among women of similar age who underwent postpartum partial salpingectomy (31.9 vs. 1.2 ectopic pregnancies per 1000 procedures). The annual rate of ectopic pregnancy for all methods combined in the 4th through 10th years after sterilization was no lower than that in the first 3 years. CONCLUSIONS: A history of tubal sterilization does not rule out the possibility of ectopic pregnancy, even many years after the procedure.
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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 $142 ($54) with emergency contraceptive pills and $119 ($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 $263 to $498 ($99 to $205) annually. CONCLUSIONS: Emergency contraception is cost-effective whether provided when the emergency arises or in advance to be used as needed. Greater use of emergency contraception could reduce the considerable medical and social costs of unintended pregnancies.
OBJECTIVE: To determine whether failure of the Yuzpe method of emergency contraception (which involves taking a higher than usual dose of ordinary combined oral contraceptives within 72 hours after unprotected intercourse, with a second dose taken 12 hours later) depends on the interval between intercourse and treatment. DATA SOURCES: We searched the literature for studies in which investigators separately reported both the number of women treated with the Yuzpe regimen and the resulting pregnancies when treatment was started on the first, second, and third days after unprotected intercourse. Searches of the electronic data bases MEDLINE, POPLINE, EMBASE, and BIOSIS were supplemented by scrutiny of the bibliographies of all papers identified through the electronic search. METHODS OF STUDY SELECTION: We identified nine published studies that present the number of women treated and outcome of treatment by time since unprotected intercourse. We included all nine studies in our analysis. TABULATION, INTEGRATION, AND RESULTS: Differences in failure rates by time of treatment adjusted for study-site effects were analyzed using logistic regression. We found no significant differences in failure rates when therapy was started on the first, second, or third day after unprotected intercourse. The large sample size ensured a power of 76% to reject the null hypothesis of equal failure rates when the odds of failure on the third day are twice those on the first and second days. CONCLUSION: Our results have two clinical implications. First, insistence on taking the first dose as soon as possible may be counterproductive in circumstances when taking the second dose 12 hours later would be difficult. Second, clinical protocols that deny treatment after 72 hours may be excessively restrictive, particularly if the alternative of emergency insertion of a copper intrauterine device is not immediately available or appropriate.
We present a conceptual model that outlines the four measures of how well a contraceptive method works: 1) efficacy, 2) effectiveness, 3) perfect-use pregnancy rate, and 4) typical-use pregnancy rate. Moreover, we illustrate how four variables influence these measures: 1) capacity to conceive, 2) frequency and timing of intercourse, 3) degree of compliance, and 4) inherent protection of the method. Because of inter-individual as well as intra-individual variability of the first three variables, generalizing results from a contraceptive clinical trial to other populations is problematic. There is a hierarchy of generalizability of the four outcome measures, with the typical-use pregnancy rate the least generalizable but the easiest to measure, and efficacy the most generalizable but the most difficult to measure. These four variables should be considered in the design and analysis of future contraceptive clinical trials. Finally, this article illustrates why the terms "pregnancy rate" and "failure rate" are not synonymous and why we recommend that the latter term not be used.