Increasing the chances of natural conception: opinion statement from the the brazilian federation of gynecology and obstetrics associations - FEBRASGO committee of gynecological endocrinology / Aumentando as chances de concepção natural: parecer da comissão nacional de ginecologia endócrina da Federação Brasileira das Associações de Ginecologia e Obstetrícia

Abstract Considering that myths and misconceptions regarding natural procreation spread rapidly in the era of easy access to information and to social networks, adequate counseling about natural fertility and spontaneous conception should be encouraged in any kind of health assistance. Despite the fact that there is no strong-powered evidence about any of the aspects related to natural fertility, literature on how to increase the chances of a spontaneous pregnancy is available. In the present article, the Brazilian Federation of Gynecology and Obstetrics Associations (FEBRASGO, in the Portuguese acronym) Committee on Endocrine Gynecology provides suggestions to optimize counseling for non-infertile people attempting spontaneous conception.

Resumo Uma vez que mitos e equívocos sobre a procriação natural se espalham rapidamente na era do fácil acesso à informação e às redes sociais, o aconselhamento adequado sobre a fertilidade natural e a concepção espontânea deve ser encorajado em qualquer tipo de assistência à saúde. Apesar do fato de não haver evidências fortes sobre qualquer dos aspectos relacionados à fertilidade natural, existe literatura sobre como aumentar as chances de uma gravidez espontânea. No presente artigo, a Comissão Nacional de Ginecologia Endócrina da Federação Brasileira das Associações de Ginecologia e Obstetrícia (FEBRASGO) oferece sugestões para otimizar o aconselhamento a pessoas que tentam a concepção espontânea, na ausência do diagnóstico de infertilidade.

Lactation, nutrition and fertility and the secretion of prolactin and gonadotrophins in Mopan Mayan women.

The effect of lactation on menstrual cycles, ovulation and conception was studied in a group of non-contracepting Amerindian Mopan Mayan women. Anthropological observations of relevant events were made over a 21-month period. Blood samples were assayed to determine the plasma concentrations of prolactin, luteinising hormone, follicle stimulating hormone, human chorionic gonadotrophin, placental lactogen, oestrogen, progesterone and cortisol. The data show that: frequent and prolonged breast-feeding was associated with a marked increase in plasma prolactin concentrations to levels similar to those in lactating Gaing but higher than those in lactating Scottish women; ovulatory menstrual cycles and pregnancy occurred during frequent lactation; in lactating menstruating women there was an inverse correlation between fat weight and months post-partum. These data suggest that other factors as well as suckling account for the effects of lactation on fecundity.

PIP: Lactation, ovulation and conception were observed as part of an anthropological study of Amerindian Mopan Mayan women from the village of San Jose Hawaii in western Belize from March 1985-January 1987. Single blood samples from each subject were immunoassayed for prolactin, LH, FSH, hCG, placental lactogen, estrogen, progesterone and cortisol. Anthropomorphic data analyzed were body mass index (BMI), fat/weight percentage, total body water and lean body weight. 117 women had at least 1 child during the study; 91 were lactating; 51 reported no menstrual cycles. 50 submitted to blood testing. Almost all infants were breast fed for 18 months or longer, up to 3 years, typically at least 6 times per day and 3 times per night. Women averaged 9 live births and 8 surviving children, with a mean birth interval of 28 months. 25 of the 29 women known to be pregnant conceived while lactating. 16 lactating women were pregnant. Their culture requires them to have 3 menses before conception to nourish the fetus, yet forbids speaking about menstrual blood: women fabricated menstrual dates, but in confidence 51 of 81 stated that they did not menstruate before the last conception. Most often menses began 12 months postpartum. Lactating women had heightened prolactin levels even if supplementing their children's diet. Thus frequent lactation delayed onset of menses, but supplementation had no effect. Most of the women were within the normal range of BMI, but 13% were below normal. In lactating menstruating women there was a significant negative correlation between fat weight and postpartum month. The data suggest that the interval to conception or menstruation was inversely correlated with fat weight. Here suckling frequency rather than prolactin levels seems to postpone fertility. In this society, with 10-12 births and 9-10 children in the completed family, the largest in the world, prolonged frequent lactation has little effect on fertility. Instead, birth trauma, maternal mortality, fetal and infant mortality, and perhaps nutrition, have more effect on completed family size.

High fertility of Old Colony Mennonites in Mexico.

Old Colony Mennonites in Mexico appear to demonstrate natural fertility, using no form of artificial birth control and apparently not attempting to limit family size. The resulting fertility is nearly as high as that of the Hutterites, although the Mennonites lack the communal economic system of the latter. Most Mennonites in Mexico migrated from Canada in the 1920s, and the largest single settlement, called the Manitoba Colony, is one of four in the state of Chihuahua. A 1967 partial census obtained data from 38% of the Mennonite households. Family size in the sample was close to that in a local survey taken in the same year. Available church records matched with census forms permitted verification of and corrections to 560 female reproductive histories. The median number of live births to women over age 45 years was 9.5, compared with 10.4 in the Hutterites. Age-specific marital fertility rates and birth intervals closely resembled those of the Hutterites.

PIP: Old Colony Mennonites in Mexico appear to demonstrate natural fertility, use no form of artificial birth control, and are apparently not attempting to limit family size. The resulting fertility is nearly as high as that of the Hutterites, although the Mennonites lack the communal economic system of the latter group. Most Mennonites in Mexico migrated from Canada in the 1920s and the largest single settlement, called the Manitoba Colony, is 1 of 4 in the state of Chihuahua. A partial census in 1967 obtained data from 38% of the Mennonite households. Family size in the sample was close to that of a local survey taken in the same year. Available church records matched with census forms permitted verification of and corrections to 560 female reproductive histories. The median number of livebirths to women over age 45 was 9.5 compared with 10.4 in the Hutterite community. Age- specific marital fertility rates and birth intervals closely resembled those of the Hutterites.

[Changes in marital fertility in Mexico: results of two models]. / Cambios en la fecundidad marital en Mexico: resultados de dos modelos.

PIP: This document compares 2 models of marital fertility, the Coale-Trussell and Rodriguez-Cleland, and applies them to analysis of recent fertility changes in Mexico. The work briefly assesses the strengths and weaknesses of the 2 models, describes their formulations, and outlines estimation procedures. The models are used to analyze data from the 1979 Mexico Fertility Survey (MFS) and the 1987 National Survey of Fertility and Health (DHS). The work ends with a discussion of possible interpretations of the changes estimated by the models in the light of changes in proximate fertility determinants. Louis Henry's concept of natural fertility was used by Coale to develop a method to analyze the magnitude of deviations from the age pattern of natural fertility displayed by populations adopting fertility control practices. The Coale-Trussell model is popular because of its mathematical simplicity and convenience for analyzing age-specific marital fertility, but it is not able to measure spacing behavior and neglects the effects of such traditional practices as prolonged abstinence or cessation of procreation according to norms concerning the woman's age. The Rodriguez-Cleland model decomposes marital fertility by both age and duration of marriage. The model as initially proposed by Page received less attention than the Coale-Trussell model because of its apparent complexity, but recent work by Rodriguez and Cleland demonstrated its analytic potential and detailed statistical methods for its estimation. Results of the Mexican analysis suggest that both models place the beginning of the fertility decline in Mexico at the early 1970s. Although the interpretation of the Coale-Trussell model is less clear than that of the Rodriguez-Cleland model, it may be concluded that the practice of limiting the number of births was already fairly widespread in some sectors of Mexican society, principally among urban women. The Rodriguez-Cleland model provides answers to questions about the contributions of variations in age at union, spacing, and limiting births to changes in marital fertility between the 2 surveys. Almost 2/3 of the decline resulted from practices to limit fertility, which were responsible for a reduction of about 1.4 children per women 25 years after the 1st union. Spacing practices were responsible for about 1/3 of the decline, while the slight changes in age at union were responsible for only a small part of the decline in marital fertility. Although the concept of natural fertility continues to be a useful took, it is insufficient to interpret the Mexican fertility transition as a passage from natural to controlled fertility, given that considerable fertility control was already practiced at the beginning of the transition.^ieng

[Fertility in rural and urban areas of Mexico]. / La fecundidad en las areas rurales y urbanas de Mexico.

PIP: Data from 6 fertility surveys conducted in Mexico between 1969-87 were used to compare rural and urban fertility and to determine whether a significant level of contraceptive usage could be achieved in rural areas despite their lack of socioeconomic development. Age-specific marital fertility rates were calculated for the 4 national-level and 2 rural fertility surveys. The index of fertility control developed by Coale and Trussel was calculated for rural, urban, and all areas. The marital total fertility rate in rural areas declined from 10.6 in 1970 to 7.4 in 1982, a decline of 2.5% annually. From 1982-87 the annual rate of decline in rural fertility slowed to 1.6%, reaching 6.8 children in 1987. The urban marital total fertility rate declined from 7.72 in 1976 to 5.03 in 1987, while the marital total fertility rate for Mexico as a whole declined from 9.04 in 1976 to 5.85 in 1987. The indices of fertility control showed slowly increasing use of contraception in rural areas starting from the very low level of 1969. The urban index of fertility control showed some contraceptive use for all age groups in all surveys. The increases in contraceptive usage were considerable in rural areas from 1976-82 and much less marked in urban areas. From 1982-87 the inverse was observed and the fertility decline in urban areas was more marked. The condition of natural fertility found in rural areas in 1969 subsequently disappeared. Over time, fertility decline and use of contraception have intensified. Contraception is widely practiced in urban areas and is continuing to become more prevalent. The rural fertility decline in 1976-82 suggests that at least sometimes increases in fertility control are more important in rural areas than in urban areas. The theory of modernization, which holds that fertility decline in developed countries is attributable to factors associated with the process of modernization, thus comes into question. However, it is probable that a sustained fertility decline in the most depressed rural areas will be achieved only with substantial socioeconomic change.^ieng

[Proximate determinants of fertility in Cuba. The Bongaarts model]. / Determinantes proximos de la fecundidad en Cuba. Modelo de Bongaart.

"The results of the implementation of the Bongaarts method for quantitating the effects of [proximate] determinants on fertility are presented. The model used is of the multiplicative kind and relates the global fertility rate to the so called natural fertility rate. Thus, it is possible to quantitate and separate the effect of each determinant and thus find out what factors have been responsible for the rapid change in fertility [in Cuba] from 1972 on. The determinant of highest impact on the fertility level attained in each province was assessed. The most important results point [to] the use of contraceptives as the cause for the rapid decline in the fertility level and the married state as the variable conditioning provincial differences." (SUMMARY IN ENG AND FRE)