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Fertility
About: Fertility is a research topic. Over the lifetime, 29988 publications have been published within this topic receiving 681106 citations.
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150 citations
TL;DR: Findings show that women actively find means to use Western methods to achieve a 2 year minimum birth interval which essentially does not change birth intervals and total fertility.
Abstract: In 1992 in 41 villages in the North Bank region of rural Gambia researchers interviewed 2979 15-54 year old women to examine the means by which this population maintains natural fertility birth intervals. Only 3.3% had ever had formal schooling. The total fertility rate was 7.5. Criteria the women used in their decision making process about contraception included effectiveness confidentiality speed with which fecundity returns after the practice ends and risk of long-term fertility impairment. Women practice postpartum abstinence for 5-7 months. Birth intervals were around 33 months. Just 5.4% of all married women with at least 1 child used Western contraceptive methods (i.e. oral contraceptives the condom or Depo-Provera). Most of the use of Western contraceptives (55%) occurred within 18 months postpartum especially 12-17 months the time when most womens fecundity returns. Few women used them for more than a few months however. After 30 months they stopped using all forms of preventing pregnancy (Western local and abstinence) suggesting that they do not intend to reduce fertility but to control its timing. Most contraceptors (69%) who had had sex in the last month used a Western contraceptive compared to just 33% of those who were not sexually active. Women were most likely to use any contraception once they begin to supplement breast milk with other foods and least likely once they wean the child indicating that they are planning for another pregnancy. Even though younger women of higher parity (5-6) were more likely to use any contraception than older women of even higher parity (9-10) they were more likely to use abstinence or traditional means to assure a return to fertility. Among older high-parity women Depo-Provera was the most common method surpassing traditional methods. These findings show that women actively find means to use Western methods to achieve a 2 year minimum birth interval which essentially does not change birth intervals and total fertility.
150 citations
TL;DR: In this article, a new set of tempo-adjusted period parity progression measures was introduced to account for two distinct implications caused by delays in childbearing: tempo distortions imply an underestimation of the quantum of fertility in observed period data, and fertility aging effect reduces higher parity births because the respective exposure is shifted to older ages when the probability of having another child is quite low.
Abstract: In this paper we introduce a new set of tempo-adjusted period parity progression measures in order to account for two distinct implications caused by delays in childbearing: tempo distortions imply an underestimation of the quantum of fertility in observed period data, and the fertility aging effect reduces higher parity births because the respective exposure is shifted to older ages when the probability of having another child is quite low. Our measures remove the former distortion and provide means to assess the latter aging effect. The measures therefore provide a unified toolkit of fertility indices that (a) facilitate the description and analysis of past period fertility trends in terms of synthetic cohort measures, and (b) allow the projection of the timing, level and distribution of cohort fertility conditional on a specific postponement scenario. Due to their explicit relation to cohort behavior, these measures extend and improve the existing adjustment of the total fertility rate. We apply these methods to Sweden from 1970 to 1999.
150 citations
TL;DR: There is a growing body of literature looking at the interplay between an individual's residential and other careers in the life course as mentioned in this paper and previous research has mostly studied the impact of partnersh...
Abstract: There is a growing body of literature looking at the interplay between an individual's residential and other careers in the life course. Previous research has mostly studied the impact of partnersh...
150 citations
TL;DR: This is the first US study to demonstrate a prospective association between salivary stress biomarkers and TTP, and the first in the world to observe an association with infertility.
Abstract: study question: Are women’s stress levels prospectively associated with fecundity and infertility? summaryanswer: Higher levels of stress as measured by salivary alpha-amylase are associated with a longer time-to-pregnancy (TTP) and an increased risk of infertility. what is known already: Data suggest that stress and reproduction are interrelated; however, the directionality of that association is unclear. studydesign,size,duration: In 2005–2009, we enrolled 501 couples in a prospective cohort study with preconception enrollment at two research sites (Michigan and Texas, USA). Couples were followed for up to 12 months as they tried to conceive and through pregnancy if it occurred. A total of 401 (80%) couples completed the study protocol and 373 (93%) had complete data available for this analysis. participants/materials,setting,methods: Enrolled women collected saliva the morning following enrollment and then the morning following their first observed study menses for the measurement of cortisol and alpha-amylase, which are biomarkers of stress. TTP was measured in cycles. Covariate data were captured on both a baseline questionnaire and daily journals. main results and the role of chance: Among the 401 (80%) women who completed the protocol, 347 (87%) became pregnant and 54 (13%) did not. After adjustment for female age, race, income, and use of alcohol, caffeine and cigarettes while trying to conceive, women in the highest tertile of alpha-amylase exhibited a 29% reduction in fecundity (longer TTP) compared with women in the lowest tertile [fecundability odds ratios (FORs) ¼ 0.71; 95% confidence interval (CI) ¼ (0.51, 1.00); P , 0.05]. This reduction in fecundity translated into a .2-fold increased risk of infertility among these women [relative risk (RR) ¼ 2.07; 95% CI ¼ (1.04, 4.11)]. In contrast, we found no association between salivary cortisol and fecundability. limitations, reasons for caution: Due to fiscal and logistical concerns, we were unable to collect repeated saliva samples and perceived stress questionnaire data throughout the duration of follow-up. Therefore, we were unable to examine whether stress levels increased as women continued to fail to get pregnant. Our ability to control for potential confounders using time-varying data from the daily journals, however, minimizes residual confounding. wider implications of the findings: This is the first US study to demonstrate a prospective association between salivary stress biomarkers and TTP, and the first in the world to observe an association with infertility.
149 citations