RESUMEN
The calendar method is perceived to be less effective than other methods of family planning. A large existing data set was used to determine how well the fertile time is identified using the traditional calendar method formula and to determine if better formulas could be developed to identify the fertile time more accurately and require less abstinence. We compared the traditional formula with three alternatives, two of which were developed for this analysis. All three alternative formulas performed better than the traditional formula in identifying the presumed fertile time. The result of our analysis is a summary table which can be used to select the best rules for testing the effectiveness of the calendar method.
PIP: While it is difficult to assess the effectiveness of the calendar method of ovulation prediction, the method is perceived to be less effective than other means of family planning (FP). In order to derive a formula(s) that identifies the ovulation accurately and minimizes the number of days of abstinence required, data from the World Health Organization's trial of the Ovulation Method of Natural FP (in which examination of cervical mucus was used to determine ovulation) were analyzed. This analysis used cycle length and peak fertile day to develop and compare the traditional calendar method formula (which calls for abstinence from day 10 to 18, inclusively) to a blanket formula (which calls for abstinence from day 9 to 19, inclusively), a midcycle formula (which calls for abstinence from day 10 to 18, inclusively, for a woman whose cycles vary from 26 to 30 days), and an average midcycle formula (which calls for abstinence from day 8 to 20, if a woman's past six cycles were 28, 27, 26, 29, 30, and 28 days). For each formula, coverage at peak day was assessed. The average midcycle and blanket formulas predicted the fertile phase most accurately, and the traditional formula performed the least favorably (since peak day increase about one half-day instead of one-to-one as cycle length increases). Any introduction of a calendar method of FP should be accompanied by basic education about how the method works.
Asunto(s)
Fertilidad , Ciclo Menstrual , Detección de la Ovulación/métodos , Servicios de Planificación Familiar , Femenino , Humanos , MatemáticaRESUMEN
OBJECTIVE: To equip the reader with the tools necessary to evaluate studies of natural family planning (NFP) effectiveness found in the literature and to make recommendations for future NFP effectiveness studies. DESIGN: Current standards to evaluate contraceptive method effectiveness are reviewed. A framework for evaluating reports on NFP is presented. RESULTS: Most NFP studies found in the literature are flawed in design and do not calculate pregnancy rates correctly. The results from the few well-designed studies are presented. DISCUSSION: Many factors influence NFP effectiveness, and these factors must be considered when evaluating published studies and designing future studies.
Asunto(s)
Servicios de Planificación Familiar , Métodos Naturales de Planificación Familiar , Anticoncepción , Estudios de Evaluación como Asunto , Femenino , Humanos , Masculino , EmbarazoRESUMEN
OBJECTIVE: To estimate the unplanned pregnancy rate of calendar rhythm. DESIGN: Meta-analysis of eight studies of calendar rhythm published between 1940 and 1989. RESULTS: There exist few studies of the calendar rhythm method. Analysis of the best of these studies resulted in a conservative estimated Pearl rate of 18.5 +/- 1.8, and a less conservative estimate of 15.0 +/- 4.0, standardized to 12 months' observation; these results are in the range of other natural and barrier methods. DISCUSSION: We need properly done clinical trials of the calendar rhythm method to scientifically establish its effectiveness.
Asunto(s)
Métodos Naturales de Planificación Familiar , Embarazo/estadística & datos numéricos , Femenino , Humanos , Detección de la Ovulación/métodos , Periodicidad , Embarazo/fisiología , Índice de Embarazo , Reproducibilidad de los ResultadosRESUMEN
PIP: Withdrawal, barrier method use, and sexual abstinence are fertility awareness-based family planning methods. They depend on a woman being able to identify the fertile period during each menstrual cycle. Identification of potentially fertile days allows couples to time intercourse either to avoid or to achieve pregnancy. A basic understanding about fertility puts couples in a better position to understand how any family planning method works and to choose the best method for their circumstances. For example, use of a barrier method or withdrawal requires a couple to clearly understand the importance of using the method consistently and correctly during the fertile period. Fertility awareness also helps couples know that most family planning methods do not affect their longterm fertility. Familiarity with fertility signs allows a woman to detect a change in her usual patterns and to seek health care at an early stage of a developing health problem. Use of natural family planning methods can be very important in areas where contraceptives are costly or their supply is unreliable. Most family planning programs do not provide fertility awareness education. Some studies indicate that combining fertility awareness with the use of barrier methods or withdrawal during the fertile period is an acceptable option to using barriers or withdrawal all the time. To identify the fertile period, women need to observe cervical secretions, to monitor basal body temperature, to use calendar calculations based upon cycle length, or to use a combination of these indicators. Development of new ways to improve fertility awareness include new rules that are better able to detect the fertile period and are easier to use and a home test kit tracking cycle length and hormone metabolites in urine. The University of Oxford in the UK is conducting a clinical trial examining the impact of fertility awareness education among condom users. It specifically aims to determine whether fertility awareness education improves the consistent use of condoms during the fertile period.^ieng
Asunto(s)
Coito Interrumpido , Anticoncepción , Consejo , Servicios de Planificación Familiar , Menstruación , Detección de la Ovulación , Educación Sexual , Abstinencia Sexual , Instituciones de Atención Ambulatoria , Técnicas de Laboratorio Clínico , Países Desarrollados , Diagnóstico , Educación , Europa (Continente) , Planificación en Salud , Organización y Administración , Reproducción , Reino UnidoRESUMEN
A pilot study was conducted in Ireland to test the effectiveness of the calendar method of contraception. A conservative rule was used, requiring on average 16 days of abstinence per cycle. Among the 19 couples who entered into the study and were followed for up to seven cycles, there were no pregnancies. Since the length of abstinence was relatively long, we collected data to determine how couples expressed love and affection towards each other during those days when the woman was potentially fertile. We also collected data about barrier method use during the fertile time. We found that almost all couples gave each other hugs and kisses to show affection although couples were taught to abstain from vaginal intercourse during the fertile time. About one-third of the couples avoided genital contact, while about half reported using oral sex and/or frottage (body rubbing). Twice as many men reported using masturbation compared to women, although about half of the couples practiced mutual (partner) masturbation. In addition, about one-fifth of the couples used condoms during the fertile time in some cycles. These findings show that a variety of sexual expressions are used by couples when vaginal intercourse is to be avoided. Knowledge about these alternative sexual expressions may be important for couples who wish to engage in sexual activity and to avoid pregnancy.
Asunto(s)
Coito , Fertilidad , Métodos Naturales de Planificación Familiar , Conducta Sexual , Condones , Femenino , Humanos , Irlanda , Masculino , Masturbación , EmbarazoRESUMEN
Natural methods of fertility regulation are acceptable in most cultures. Many couples worldwide do not wish to use contraceptives or do not have access to them but wish to limit their family size or lengthen the time between births. Barriers to expanding use of natural family planning (NFP) methods include a lack of providers who can teach NFP and a lack of time to teach and follow couples during the initial months of NFP use. If simple yet effective methods of NFP are available, then NFP could be introduced to a wider audience. Recently, calendar rules have been revised that use a set interval to identify fertile days. These new rules provide better coverage of fertile days and require less abstinence than the rules traditionally used with the calendar method. One of these new rules is being field tested in a pilot study in Brazil. Couples are asked to abstain from day 9-19 (inclusive) of the menstrual cycle, using a beaded necklace (the 'collar') as a mnemonic device. Focus groups with the teacher-monitors and in-depth interviews with female and male users were carried out to evaluate the acceptability of the 'collar' method. A preliminary analysis of these focus groups and interviews from the first site is presented.
Asunto(s)
Servicios de Planificación Familiar/métodos , Métodos Naturales de Planificación Familiar , Brasil , Femenino , Fertilidad , Grupos Focales , Humanos , Masculino , Detección de la Ovulación , Educación del Paciente como Asunto , Proyectos PilotoRESUMEN
The occurrence and duration of the fertile period in women are strictly related to the time of ovulation. Since the only positive confirmation of ovulation is the identification of an ovum in the female reproductive tract or the subsequent detection of a pregnancy, the prediction and detection of its occurrence have to be based on markers or indicators that lie at varying physiological distances from ovulation itself. These may be variations in hormones and other substances that can be detected in different body fluids or the evidence of their effects on specific target organs. Recent advances in the knowledge of reproductive physiology have allowed the identification of distinct substances and biological phenomena that accompany the occurrence of the fertile period. This article is intended to update and classify the available fertility markers based on their particular nature and modality of expression and, additionally, consider the temporal relationship between the appearance of their specific signals and the time of ovulation. Consequently, those indicators directly related to changes at the ovarian level were defined as direct markers, including ovarian morphology, the reproductive hormones, and the intraovarian regulatory proteins, whereas those reflecting variations observed in different target organs were considered indirect markers, and were further qualified as biochemical, biophysical, and clinical. Subsequently, fertility markers were classified as prospective, immediate, or retrospective, depending on whether they allow the prediction, detection, or confirmation of the ovulatory event, respectively.