A 2-year international study involving NFP (natural family planning) associations in 5 countries (Canada Colombia France Mauritius U.S.) was conducted to evaluate statistically the effectiveness of the sympto-thermal method an NFP method which adds to the temperatiure method the observation of signs and symptoms of the ovulatory period. 1022 couples (21736 couples) were selected on the following criteria: 1) the wife had to be between 19 and 44 years of age 2) the wife had to be of proven fertility by having carried a fetus for at least 28 weeks 3) the couple must have submitted 1 satisfactory temperature graphy before being accepted and 4) the couple must have expressed a willingness to submit temperature graphs for 2 years. 826 couples completed 24 months. Menstrual cycle length varied from 9 to 98 days with an average of 28.43 days. 205 women had a variation of 8 days or less. 128 unplanned pregnancies occured giving a rate of 7.47 conceptions/100 woman-years of exposure. Theoretical effectiveness was .93 pregnancies/100 woman-years using the Pearl Formula; 16 pregnancies occured in couples following instructions. Failure rate was 4.13% for couples trying to prevent pregnancies and 14.83% for couples only delaying a pregnancy. Failure rate of the method used alone was 7.16%; 8.19% used with other contraceptives. There was an average of 13 cycles per year per woman. Using the modified Pearl index (pregnancies per 1300 cycles rather than per 1200 months) the pregnancy rate was 7.66% vs. 7.47% for 1200 months. The study shows that the sympto-thermal method is effective and reliable. 2 issues remain unresolved: 1) whether a large group of people will accept a method that depends on periodic abstinence or 2) whether the method will be just as effective when used by couples who are not as well motivated as the participants in this study.
sympto-thermal method effectiveness natural family planning, NFP international study Pearl index pregnancy rate, sympto-thermal method unplanned pregnancy rate, Rice Lanctôt NFP effectiveness study, periodic abstinence fertility awareness effectiveness, natural family planning theoretical vs use effectiveness, temperature method combined ovulatory signs NFP, sympto-thermal method motivation compliance abstinence, menstrual cycle variation natural family planning, NFP method failure rate delaying vs preventing pregnancy, international multicenter natural family planning trial
Cite this article
Rice, F. J., Lanctôt, C. A., & Garcia-Devesa, C. (1981). Effectiveness of the sympto-thermal method of natural family planning: an international study. International journal of fertility, 26(3), 222-230.
Rice FJ, Lanctôt CA, Garcia-Devesa C. Effectiveness of the sympto-thermal method of natural family planning: an international study. Int J Fertil. 1981;26(3):222-230.
Rice, Frank J., et al. "Effectiveness of the sympto-thermal method of natural family planning: an international study." International journal of fertility, vol. 26, no. 3, 1981, pp. 222-230.
Mutations in the methylenetetrahydrofolate reductase (MTHFR) gene (677C>T, 1298A>C) cause elevated plasma homocysteine concentrations and have been linked to fatal outcomes after nitrous oxide anesthesia. This study tested the hypothesis that patients with common MTHFR 677C>T or 1298A>C mutations develop higher plasma homocysteine concentrations after nitrous oxide anesthesia than wild-type patients. In this prospective, observational cohort study with blinded, mendelian randomization, the authors included 140 healthy patients undergoing elective surgery. All patients received 66% nitrous oxide for at least 2 h. The main outcome variable, plasma total homocysteine, and folate, vitamin B12, and holotranscobalamin II were measured before, during, and after surgery. After completion of the study, all patients were tested for their MTHFR 677C>T or 1298A>C genotype. Patients with a homozygous MTHFR 677C>T or 1298A>C mutation (n = 25) developed higher plasma homocysteine concentrations (median [interquartile range], 14.9 [10.0-26.4] microm) than wild-type or heterozygous patients (9.3 [7.5-15.5] microm; n = 115). The change in homocysteine after nitrous oxide anesthesia was tripled in homozygous patients compared with wild-type (5.6 microm [+60%] vs. 1.8 microm [+22%]). Only homozygous patients reached average homocysteine levels considered abnormal (> 15 microm). Plasma 5-methyl-tetrahydrofolate concentrations increased uniformly by 20% after nitrous oxide anesthesia, indicating the inactivation of methionine synthase and subsequent folate trapping. Holotranscobalamin II concentrations remained unchanged, indicating no effect of nitrous oxide on vitamin B12 plasma concentrations. This study shows that patients with a homozygous MTHFR 677C>T or 1298A>C mutation are at a higher risk of developing abnormal plasma homocysteine concentrations after nitrous oxide anesthesia.
To examine the risk of multiple sclerosis in users of combined oral contraceptives.
Cohort study conducted between 1968 and 1996 using diagnostic data supplied by General practices throughout the United Kingdom. Royal College of General Practitioners' Oral Contraception Study cohort of initially 46,000 women recruited during the late 1960s. Directly standardised incidence rates of multiple sclerosis were calculated for current, former and never-users of oral contraceptives using first ever cases of multiple sclerosis reported by the general practitioners. The standardisation variables were age, parity, social class and smoking history. Five-year survival rates in the different contraceptive groups were calculated using standard life table techniques. One hundred and fourteen first ever cases of multiple sclerosis had been reported by November 1996 during 564,000 woman-years of observation. The incidence rate in both current and former users was not materially different to that in never-users. Although based on limited evidence there was no suggestion that the five-year survival was affected by a woman's use of combined oral contraceptives. These findings do not suggest a greatly elevated risk of multiple sclerosis during, or after, use of combined oral contraceptives.
Bone HealthOsteoporosis Incidence and PrevalenceProspective CohortFracture Risk Assessment
Relatively little is known about the factors in Canada which lead to osteoporosis and its concomitant fractures. The Canadian Multicentre Osteoporosis Study (CaMos) is a prospective cohort study which will estimate the incidence and prevalence of declining bone mass and fractures. The impact of osteoporosis in Canada will be assessed, including regional variation and the effect of various risk factors. The study will provide information for developing prevention programs. The cohort has been drawn from a random population-based sample of non-institutionalized men and women 25 years old or more and living within 50 km. of nine cities in Canada. Through telephone interviews 9,423 participants have been recruited. All answered an extensive questionnaire, and had physical measurements related to bone quality taken. This paper details the CaMos baseline and five-year follow-up protocol.
Fertility AwarenessNFP Status ReportEffectivenessBillings Method Effectiveness
The current status of natural family planning (NFP) was reviewed. There is renewed interest in NFP, and many couples who find other methods unacceptable for medical, safety, or personal reasons are turning to NFP methods. The percent of contraceptive users who rely on behavioral methods in developing countries in 35% in Peru, 20%-25% in Haiti, Philippines, and Sri Lanka, and average 7.5% for the remaining 23 developing countries. IN the US about 4.7% of all contraceptive users rely on behavioral methods. Worldwide, rhythm is the most commonly used form of behavior fertility control, but this method is not promoted by most NFP programs. The 3 modern methods of NFP are 1) the basal body temperature method, 2) the cervical mucus, or Billings method, and 3) the sympto-thermal method. All these methods rely on physical signs and symptoms to detect ovulation and require sexual abstinence during the fertile phase of the menstrual cycle. The basal body temperature method requires women to detect the slight rise in temperature which occurs at the time of ovulation. The method is 94%-97% effective if intercourse is restricted to the postovulatory phase of the cycle. Disadvantages of the method are that intercourse must be restricted to only 7-13 days of the cycle, women must take their temperature daily, the method cannot be used during fever episodes, and the method is inappropriate for use during lactation or near menopause. The cervical mucus method is based on observing cervical mucus changes during the cycle. These changes signal the fertile and infertile phases of the cycle. According to a World Health Organization study, 93% of the women instructed in the method were able to detect mucus changes, and illiterate women were as adept at identifying these changes as university graduates. Findings also indicated that the method was 97% effective if abstinence was practiced during 15 days of the cycle, but use-effectiveness was only about 80%. This method has the advantage of not requiring ovulatory regularity. The sympto-thermal method uses a combination of symptoms including temperature shifts and mucus changes to detect ovulation. Some studies indicate that the combined method is more effective than those methods based on only 1 symptom, but many individuals find the combined method difficult and confusing. The advantages of NFP methods are that they require no medical supervision and that they have no side effects. Family planning providers often have negative attitudes toward NFP and many programs do not provide NFP services. Many providers maintain that the methods are ineffective and difficult to apply and that there is little demand for NFP. Research should be undertaken to determine if these opinions are valid. The major source of funding for NFP programs and projects is the US Agency for International Development (USAID). The agency is currently supporting 22 NFP projects under USAID grants and another 16 bilateral NFP programs. The research undertaken in connection with these projects should provide needed information on NFP advantages, disadvantages, effectiveness, and demand.