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J Trussell

Publications and source records attributed to J Trussell.

At least 55 records · Page 3Linked to original sources
PubMed1996

Measuring contraceptive effectiveness: a conceptual framework.

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.

Clinical Trials as Topic↗
PubMed1996

The risk of pregnancy after tubal sterilization: findings from the U.S. Collaborative Review of Sterilization.

OBJECTIVE: Our purpose was to determine the risk of pregnancy after tubal sterilization for common methods of tubal occlusion. STUDY DESIGN: A multicenter, prospective cohort study was conducted in U.S. medical centers. A total of 10,685 women who underwent tubal sterilization was followed up for 8 to 14 years. The risk of pregnancy was assessed by cumulative life-table probabilities and proportional hazards models. RESULTS: A total of 143 sterilization failures was identified. Cumulative 10-year probabilities of pregnancy were highest after clip sterilization (36.5/1000 procedures) and lowest after unipolar coagulation (7.5/1000) and postpartum partial salpingectomy (7.5/1000). The cumulative risk of pregnancy was highest among women sterilized at a young age with bipolar coagulation (54.3/1000) and clip application (52.1/1000). CONCLUSIONS: Although tubal sterilization is highly effective, the risk of sterilization failure is higher than generally reported. The risk persists for years after the procedure and varies by method of tubal occlusion and age.

Age Factors↗
PubMed1996

The development and use of demographic models.

In this review, we first examine two classical demographic models - conventional life tables and stable populations - and a modern generalization of stable population theory; we then discuss mathematical models of conception and birth. These models involve purely mathematical relations in formal demography as opposed to empirical regularities. Next we consider model age schedules of mortality, nuptialitiy, marital fertility, fertility, and migration that are explicitly based on such empirical patterns. We close this empirical section with a discussion of model stable populations, which are based on model life tables. We next examine the use of demographic models in forecasting future mortality, nuptiality, and fertility and in population projection. Following a discussion of microsimulation models, which gives us the opportunity to mention model age schedules of post partum amenorrhoea and of sterility, we close with observations about the purposes and uses of demographic models.

Demography↗
PubMed1995

Condom use among female commercial sex workers in Nevada's legal brothels.

OBJECTIVES: The purpose of this study was to evaluate condom use and the incidence of breakage and slippage during vaginal intercourse among female prostitutes in legal Nevada brothels, where use of condoms is required by law. METHODS: Forty-one licensed prostitutes in three brothels were enrolled in a prospective trial in August 1993. Used condoms were collected to verify reported breaks visually. Retrospective breakage and slippage rates were obtained in a standardized interview. RESULTS: Condoms were used for every act of vaginal intercourse with a brothel client during the study period, as well as in the previous year. In the prospective study phase, condoms were used in 353 acts of vaginal intercourse with clients. No condoms broke, and none fell off the penis during intercourse. Only twice (0.6%) did condoms completely fall off during withdrawal. Twelve times (3.4%) during intercourse and 15 times (4.3%) during withdrawal, condoms slipped down the penis but did not fall off. CONCLUSIONS: These findings, among the lowest breakage and slippage rates published, suggest that regular condom use may lead to condom mastery and the development of techniques to reduce the likelihood of breakage and slippage.

Adult↗
PubMed1995

The economic value of contraception: a comparison of 15 methods.

OBJECTIVES: The purpose of the study was to determine the clinical and economic impact of alternative contraceptive methods. METHODS: Direct medical costs (method use, side effects, and unintended pregnancies) associated with 15 contraceptive methods were modeled from the perspectives of a private payer and a publicly funded program. Cost data were drawn from a national claims database and MediCal. The main outcome measures included 1-year and 5-year costs and number of pregnancies avoided compared with use of no contraceptive method. RESULTS: All 15 contraceptives were more effective and less costly than no method. Over 5 years, the copper-T IUD, vasectomy, the contraceptive implant, and the injectable contraceptive were the most cost-effective, saving $14,122, $13,899, $13,813, and $13,373, respectively, and preventing approximately the same number of pregnancies (4.2) per person. Because of their high failure rates, barrier methods, spermicides, withdrawal, and periodic abstinence were costly but still saved from $8933 to $12,239 over 5 years. Oral contraceptives fell between these groups, costing $1784 over 5 years, saving $12,879, and preventing 4.1 pregnancies. CONCLUSIONS: Contraceptives save health care resources by preventing unintended pregnancies. Up-front acquisition costs are inaccurate predictors of the total economic costs of competing contraceptive methods.

Contraception↗
PubMed1995

Contraceptive efficacy.

"Will it work?" is the question usually asked first and most frequently about any contraceptive method. This question is especially salient for women using teratogenic drugs and their clinicians, particularly dermatologists. As discussed in other articles in this issue of the ARCHIVES, dermatologists prescribe two of the most potent teratogenic drugs, isotretinoin (Accutane, Roche Laboratories, Nutley, NJ) and thalidomide. Because this question cannot be answered with certainty for any particular couple, most clinicians and counselors try to help patients understand factors influencing contraceptive efficacy.

Abnormalities, Drug-Induced↗
PubMed1994

Women's reproductive cancers in evolutionary context.

Reproductive experiences for women in today's affluent Western nations differ from those of women in hunting and gathering societies, who continue the ancestral human pattern. These differences parallel commonly accepted reproductive risk factors for cancers of the breast, endometrium and ovary. Nutritional practices, exercise requirements, and body composition are nonreproductive influences that have been proposed as additional factors affecting the incidence of women's cancers. In each case, these would further increase risk for women in industrialized countries relative to forager women. Lifestyles and reproductive patterns new from an evolutionary perspective may promote women's cancers. Calculations based on a theoretical model suggest that, to age 60, modern Western women have a breast cancer risk as much as 100 times that of preagricultural women.

Biological Evolution↗
PubMed1994

Standardized protocols for condom breakage and slippage trials: a proposal.

In the absence of well-controlled studies on the clinical effectiveness of condoms against pregnancy and sexually transmitted diseases, breakage and slippage data may provide the best indication of the protection offered by condom use. According to the recent literature, condom breakage rates range from 0% to 12%, with many US studies falling in the 2% to 5% range. Few studies have collected slippage data. In addition to discussing methodological issues associated with these studies, we propose a standardized protocol for future condom breakage and slippage trials and discuss how results may be used to estimate perfect-use and typical-use pregnancy rates.

Condoms↗
PubMed1994

What do we know about the timing of fertility transitions in Europe?

The Princeton project on the decline of fertility in Europe (the European Fertility Project) suggested that this historical fertility transition occurred virtually simultaneously in a wide variety of economic and social environments. This finding has been cited widely as evidence for an innovation/diffusion view of fertility transitions. We demonstrate that the demographic methods used to date the fertility transition in Europe--primarily Ig, and (to a lesser extent) the Coale-Trussell M&m indices--may fail to detect the initial stages of a fertility transition and therefore cannot be used as the basis for strong statements about the timing of transitions. We review these measurement problems and their implications for the current understanding of the European fertility transition.

Contraception↗
PubMed1993

Should oral contraceptives be available without prescription?

In this paper, it is argued that oral contraceptives should be available without prescription. Prescription status entails heavy costs, including the dollar, time, and psychological costs of visiting a physician to obtain a prescription, the financial and human costs of unintended pregnancies that result from the obstacle to access caused by medicalization of oral contraceptives, and administrative costs to the health care system. After a review and evaluation of the reasons for strict medical control of oral contraceptives in the United States, safety concerns anticipated in response to the proposal discussed here are addressed. Also, concerns that prescription status is necessary for efficacious use are evaluated. It is concluded that neither safety nor efficacy considerations justify prescription status for oral contraceptives. Revised package design and patient labeling could allow women to screen themselves for contraindications, to educate themselves about danger signs, and to use oral contraceptives safely and successfully. Several alternatives to providing oral contraceptives by prescription with current package design and labeling and selling them over the counter are suggested; the proposals discussed would make these safe and effective contraceptives easier to obtain and to use.

Contraceptives, Oral↗
PubMed1992

Condom performance during vaginal intercourse: comparison of Trojan-Enz and Tactylon condoms.

Forty-nine mutually monogamous couples used a total of 478 condoms during vaginal intercourse in a prospective trial whose purpose was to discover whether the performance of a new non-latex hypoallergenic condom was substantially equivalent to that of a leading condom brand already being marketed. Of these 478 condoms, seven (1.46%) either broke or fell off the penis during intercourse. Two (0.42%) of the 471 condoms that did not break or fall off during intercourse fell off the penis when it was being withdrawn from the vagina. Altogether, 469 (98.1%) of the 478 condoms used for intercourse survived intact throughout intercourse and withdrawal. Differences in breakage and slippage rates for the two condom brands were statistically insignificant. The overall 98.1% success rate is much higher than the rate of success found in a previous condom trial with nearly identical research protocol. The reason for the difference is attributed to much more precise questioning of subjects in the current trial.

Adult↗
PubMed1992

Contraceptive use projections: 1990 to 2010.

Factors that will affect both contraceptive use and choice of method during the next 20 years are reviewed. Two factors are predictable: the changing age distribution of women and the revised upper-age limits for oral contraceptive use, with the effect of the latter as yet unknown. Less predictable factors include the number of women in each age group at risk for pregnancy, the effects of delayed childbearing and sterilization, and the impact of new contraceptive methods. Unpredictable factors include adverse publicity about oral contraceptives and breast cancer, concern about sexually transmitted diseases and acquired immunodeficiency syndrome, and changes in the availability of legal abortion. Numbers of women using oral contraception, other reversible methods, sterilization, and no method are projected from 1990 to 2010 under the assumption that use patterns in each age group resemble those observed in 1988. We conclude that discrepancies between projections of contraceptive use and fact are likely to occur because of the unpredictable nature of these few important variables.

Abortion, Legal↗
PubMed1992

Commentary: the quest for women's prophylactic methods--hopes vs science.

The companion article by Rosenberg and Gollub in this issue summarizes data from 10 observational studies and concludes that female-controlled contraceptive methods, under typical conditions, are comparable to condoms in preventing sexually transmitted diseases and should be merchandized as such. While we agree that chemical and mechanical contraceptives provide protection against some sexually transmitted diseases, we think the authors have overstated the scientific case for these methods, especially in comparison with the condom. We think the current data remain inconclusive regarding the absolute protection of spermicides against the human immunodeficiency virus and their level of protection--relative to that of the condom--against other sexually transmitted diseases. Three reasons account for our differences: the limitations in the comparative data; the reported adverse effects of spermicides on vaginal conditions, including genital ulcers; and the relative value of condoms, even under typical conditions, in preventing sexually transmitted diseases. For these reasons, we would currently counsel both women and men who practice high-risk sexual behaviors to use condoms as their first line of defense. If this is unacceptable, the female barriers become a fallback position to protect against bacterial sexually transmitted diseases.

Condoms↗
PubMed1992

Birth spacing and child mortality in Bangladesh and the Philippines.

This analysis uses data from Bangladesh and the Philippines to demonstrate that children who are born within 15 months of a preceding birth are 60 to 80% more likely than other children to die in the first two years of life, once the confounding effects of prematurity are removed. The risks associated with short conception intervals are confined to children who are also high birth order; they persist in the presence of controls for prior familial child mortality, breast-feeding, mother's age, and socioeconomic status. In Bangladesh but not in the Philippines, these effects are confined to the neonatal period.

Bangladesh↗
PubMed1991

Methodological pitfalls in the analysis of contraceptive failure.

Although the literature on contraceptive failure is vast and is expanding rapidly, our understanding of the relative efficacy of methods is quite limited because of defects in the research design and in the analytical tools used by investigators. Errors in the literature range from simple arithmetical mistakes to outright fraud. In many studies the proportion of the original sample lost to follow-up is so large that the published results have little meaning. Investigators do not routinely use life table techniques to control for duration of exposure; many employ the Pearl index, which suffers from the same problem as does the crude death rate as a measure of mortality. Investigators routinely calculate 'method' failure rates by eliminating 'user' failures from the numerator (pregnancies) but fail to eliminate 'imperfect' use from the denominator (exposure); as a consequence, these 'method' rates are biased downward. This paper explores these and other common biases that snare investigators and establishes methodological guidelines for future research.

Contraception↗