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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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Journal ArticleDOI
TL;DR: In this article, the authors argue that the 13.5% fall in fertility over the 1970-1982 period led ob/gyns to substitute from normal childbirth toward a more highly reimbursed alternative, cesarean delivery.
Abstract: The "induced-demand" model states that in the face of negative income shocks, physicians may exploit their agency relationship with patients by providing excessive care. We test this model using an exogenous change in the financial environment facing obstetrician/gynecologists: declining fertility in the United States. We argue that the 13.5% fall in fertility over the 1970-1982 period led ob/gyns to substitute from normal childbirth toward a more highly reimbursed alternative, cesarean delivery. Using a nationally representative microdata set for this period, we show that there is a strong correlation between within-state declines in fertility and within-state increases in cesarean utilization.

305 citations

Journal ArticleDOI
TL;DR: It is concluded that sperm counts and fertilizing capacity of sperm are not negatively influenced by old age, at least not in men with sustained sexual activity, however, the pituitary as well as the testis show signs of decreased endocrine reserve capacity in old age.
Abstract: Testicular functions were investigated in 23 grandfathers [60--88 yr old; 67 +/- 7.8 (mean +/- SD)], i.e. men with fertility proven earlier in life. They were recruited from a nonpatient population and led an active life, most of them with a permanent partner. The grandfathers were compared with a group of 20 unrelated healthy fathers, 24--37 years old (29.2 +/- 3.2). Whereas sperm density was higher in the older group, there were no significant differences in ejaculate volume and sperm morphology between the younger and older men. Sperm motility and seminal fructose, however, decreased with age. The fertilizing capacity of sperm as assessed in the heterologous ovum penetration test using zona pellucida-free hamster eggs did not decrease significantly with age. Whereas the basal serum testosterone and estradiol levels were not different between the younger and older men, the response to 2 days of hCG stimulation decreased significantly with age. This decrease was observed in older men whether they had frequent or infrequent sexual activity. Basal serum LH and FSH levels were elevated in the older men. The LH response to GnRH stimulation relative to basal; values was significantly reduce, while FSH responses did not change with age. We conclude that sperm counts and fertilizing capacity of sperm are not negatively influenced by old age, at least not in men with sustained sexual activity. However, the pituitary as well as the testis show signs of decreased endocrine reserve capacity in old age.

305 citations

Journal ArticleDOI
TL;DR: Leridon as mentioned in this paper integrated biology and demography to investigate human fertility, both natural and controlled, and formulated the first coherent overview of the functioning of the human reproductive system in relation to the external conditions that affect fertility.
Abstract: In this innovative and comprehensive work, expanded by one-third for the English-language edition, Henri Leridon integrates biology and demography to investigate human fertility, both natural and controlled. Traditionally, demographers have been concerned with birthrates in different populations under varying conditions, while biologists have limited themselves to the study of the reproductive process. Leridon has formulated the first coherent overview of the functioning of the human reproductive system in relation to the external conditions that affect fertility. The book begins with a readable, authoritative review of human fertility in its natural state. Leridon summarizes and evaluates current knowledge, drawing together rare statistical data on physiological variables as well as demographic treatments of these data. After discussing the classical framework used by demographers, Leridon undertakes a "microdemographic" analysis in which he focuses on the individual and explicates the biological processes through which social, psychological, and economic factors affect fertility. He isolates its components fecundability, intrauterine mortality, the physiological nonsusceptible period, and sterility then reviews the composite effect of variation in any one component. Leridon considers situations of controlled fertility: contraception, abortion, and sterilization. The author also presents valuable new data from his own investigations of varying risks of intrauterine mortality. Finally, he shows how the previous approaches can be complemented by the use of mathematical models."

304 citations

Journal ArticleDOI
TL;DR: Although higher maternal age can be an indication for intensive prenatal diagnosis, including invasive diagnostics, consideration of the available evidence suggests that paternal age itself, however, provides no rationale for invasive procedures.
Abstract: BACKGROUND Due to various sociological factors, couples in developed countries are increasingly delaying childbearing. Besides ethical, economical and sociological issues, this trend presents us with several complex problems in reproduction. Although it is well-known that maternal age has a negative effect on fertility and increases the risk of adverse outcome during pregnancy and in offspring, the paternal influence on these outcomes is less well researched and not well-known. METHODS We performed a systematic search of PubMed, and retrieved original articles and review articles to update our previous survey in this journal. RESULTS This review highlights the link between male age and genetic abnormalities in the germ line and summarizes the knowledge about the effects of paternal age on reproductive function and outcome. Increasing paternal age can be associated with decreasing androgen levels, decreased sexual activity, alterations of testicular morphology and a deterioration of semen quality (volume, motility, morphology). Increased paternal age has an influence on DNA integrity of sperm, increases telomere length in spermatozoa and is suggested to have epigenetic effects. These changes may, at least in part, be responsible for the association of paternal age over 40 years with reduced fertility, an increase in pregnancy-associated complications and adverse outcome in the offspring. CONCLUSION Although higher maternal age can be an indication for intensive prenatal diagnosis, including invasive diagnostics, consideration of the available evidence suggests that paternal age itself, however, provides no rationale for invasive procedures.

303 citations

Book
01 Jan 1995
TL;DR: This long-awaited book presents a comprehensive, integrated and up-to-date overview of the major physiological and behavioral factors affecting human reproduction.
Abstract: Awarded the W. W. Howells Award for the Outstanding Book in Biological Anthropology, this volume presents a comprehensive, integrated, and up-to-date overview of the major physiological and behavioral factors affecting human reproduction. In attempting to identify the most important causes of variation in fertility within and among human populations, Wood summarizes data from a wide range of societies. Trained as an anthropologist as well as a demographer, he devotes special attention to so-called ""natural fertility"" populations, in which modern contraceptives and induced abortion are not used to limit reproductive output. Such an emphasis enables him to study the interaction of biology and behavior with particular clarity.The volume weaves together the physiological, demographic, and biometric approaches to human fertility in a way that will encourage future interdisciplinary research. Instead of offering a general overview, the focus is to answer one question: Why does fertility and the number of live births vary from couple to couple within any particular population, and from population to population across the human species as a whole?Topics covered include ovarian function, conception and pregnancy, intrauterine mortality, reproductive maturation and senescence, coital frequency and the waiting time to conception, marriage patterns and the initiation of reproduction, the fertility-reducing effects of breastfeeding, the impact of maternal nutrition on reproduction, and reproductive seasonality. This unique combination of comprehensive subject matter and an integrated analytical approach makes the book ideally suited both as a graduate-level textbook and as a reference work.

302 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20241
20232,042
20223,958
20211,098
20201,105
20191,047