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PubMed1974

Differentials in the rate of fertility decline: 1960-1970.

The continuous decline in fertility in the United States since 1957, while affecting all elements of the population, has been most pronounced and most rapid among those groups which previously had the highest fertility - blacks, American Indians and Mexican Americans-all of whom experienced fertility declines more rapid than those experienced by urban whites between 1957-1960 and 1967-1970. Among urban whites, fertility decline has been heavily concentrated among those of low income. The decline was especiallyrapid for third and higher order births, suggesting a heavy concentration of completed fertility at two-child families. The rapid decline, and the narrowing of the traditionalfertility differentials among various subgroups have important implications in the areasof poverty, education, the role of women in society and the dynamics of local area growth.

Black or African American↗

PubMed2026

Research progress on multi-mechanism analysis and protection strategies of ovarian aging and fertility decline.

Age-related fertility decline is an increasingly important challenge in reproductive medicine, driven largely by progressive ovarian aging. The aging ovary undergoes functional deterioration characterized by reduced ovarian reserve and declining oocyte quality, ultimately limiting female reproductive lifespan. Although multiple molecular and cellular processes associated with ovarian aging have been identified, these mechanisms are often discussed independently, limiting an integrated understanding of how they interact within the ovary. In this review, we propose an ovary-centered, multi-mechanistic framework to organize current evidence on ovarian aging and fertility decline. We discuss how genomic instability, telomere attrition, mitochondrial dysfunction, oxidative stress, chronic cellular stress responses, and alterations in ovarian signaling and microenvironmental homeostasis collectively contribute to follicle depletion and impaired oocyte competence. Particular emphasis is placed on signaling pathways involved in follicle activation and stress adaptation, including PI3K/AKT/mTOR, FOXO3, Hippo, and AMPK-Sirtuin networks, while acknowledging that many mechanistic relationships remain incompletely defined in physiological ovarian aging. Building on this integrative perspective, we further evaluate mechanism-oriented intervention strategies, including mitigation of cellular stress, metabolic and signaling modulation, optimization of the ovarian microenvironment, established fertility preservation technologies, and emerging exploratory approaches. By integrating current mechanistic and translational evidence, this review provides a conceptual framework for understanding ovarian aging and highlights future directions for evidence-based fertility preservation and reproductive health management in the context of aging.

Humans↗

PubMedDate not supplied

Women's lives in transition: a qualitative analysis of the fertility decline in Bangladesh.

The fertility decline that began in Bangladesh in the late 1980s and continues has prompted diverse theories to explain it. In this qualitative analysis of 21 focus-group sessions with rural women ranging in age from the teens to late 40s and living in the villages of the Matlab area, the women's perceptions of their changing society and of the influence of the family planning program are examined. The women's statements reveal their awareness of the social and economic transition they are undergoing and their interest in family-size limitation, which is bolstered by a strong family planning program. Although the shifts in economic and social circumstances are not large, in conjunction with the strong family planning program they constitute a powerful force for change in attitudes, ideas, and behavior among these women.

Adolescent↗

PubMed1993

Evidence for the involvement of epidermal growth factor in fertility decline in aging female mice.

A decline in fertility, defined as the number of implantation sites, was observed in mice as they aged; the decline started at 30 weeks of age and reached a nadir by 60 weeks when no implantation was detected. Epidermal growth factor (EGF) levels in the submandibular gland and plasma increased as the female mice aged, and sialoadenectomy (surgical removal of the submandibular glands) attenuated the rise in the plasma EGF level without affecting the overall health or survival of the animals. Uterine weight at 10-20 weeks of age was about 70 mg, and it significantly increased with age. This weight has increased more than 2-fold by 60 weeks. These changes closely followed the increase in the concentrations of EGF in the submandibular gland and the plasma. After sialoadenectomy, uterine weight decreased immediately and remained at about 50-60 mg throughout the experimental period. Interestingly, sialoadenectomized mice became pregnant at an older age than the controls. These findings suggest that elevated levels of EGF may have a physiological role in fertility decline in aging mice perhaps via uterine hypertrophy.

Aging↗

PubMed1994

Fertility decline in East Asia.

With the fall of fertility in China to near or below replacement levels in the early 1990s, the whole of East Asia may now be said to have completed a demographic transition. Its experience lies between that of the West and the many developing countries in which demographic transition is now under way. The main features and possible underlying causes of the fertility declines in Japan, Taiwan, South Korea, and China during this century are discussed. Fertility decline in East Asia is interesting both in its own right, as a chapter in the history of human reproduction, and for the light it may shed on fertility decline in the rest of the world.

China↗

PubMed1995

Demand or ideation? Evidence from the Iranian marital fertility decline.

Is the onset of fertility decline caused by structural socioeconomic changes or by the transmission of new ideas? The decline of marital fertility in Iran provides a quasi-experimental setting for addressing this question. Massive economic growth started in 1955; measurable ideational changes took place in 1967. We argue that the decline is described more precisely by demand theory than by ideation theory. It began around 1959, just after the onset of massive economic growth but well before the ideational changes. It paralleled the rapid growth of participation in primary education, and we found no evidence that the 1967 events had any effect on the decline. More than one-quarter of the decline can be attributed to the reduction in child mortality, a key mechanism of demand theory. Several other findings support this main conclusion.

Adolescent↗

PubMed1992

[Analysis of the fertility decline in Japan--focusing on the period of 1950-60 and 1975-85].

Marked fertility declines have been observed in Japan from 1950-60 and 1975-85. The dynamic structure of the fertility decline in the two periods was analyzed employing the Standardization Approach and Bongaarts Model of Proximate Determinants Analysis. The results indicate that the fertility decline in 1950-60 was mainly caused by a drop in marital fertility due to the expanding diffusion of contraception practices and increases in induced abortion. Increased age at marriage cannot be discounted as a factor also. The fertility decline in 1975-85 was mostly caused by delay of marriage as well as a reduction in proportion of the reproductive population which is composed of a cohort born in 1960 or later.

Adolescent↗

PubMed1985

Declining fertility in England and Wales as a major cause of the twentieth century decline in mortality. The role of changing family size and age structure in infectious disease mortality in infancy.

The decline in infectious disease mortality in England and Wales beginning about 1880 has been attributed to improved nutrition, hygiene, and sanitation. Such an explanation does not adequately explain the lack of improvement in infant and diarrheal disease mortality before 1900 nor the abrupt subsequent decline. A hypothesis was proposed that the decline in fertility rate was a major cause of the decline in infant mortality by raising the median age at infection. The hypothesis could only be tested indirectly. A review of morbidity data demonstrates the importance of family characteristics on the median age at infection for measles, pertussis, and common respiratory illness. The association of parity with infectious disease mortality supports the hypothesis. A method was developed for estimating the change in birth order distribution resulting from declining fertility. Using 1949-1950 data, it was shown that declining fertility could account for at least a 24% decline in postneonatal mortality due to bronchitis and pneumonia. Age-specific measles mortality rates are consistent, with an increase in age at infection. Declining fertility appears to have played a major role in the decline in infectious disease mortality in England and Wales by increasing the median age at infection.

Adolescent↗

PubMed1992

West Indian gender relations, family planning programs and fertility decline.

Nearly all West Indian islands initiated marked fertility declines sometime between 1960 and 1970. Family planning programs have not played an important role in these declines. Neither have other variables that conventional social theory tells us should promote reduced family sizes, like education and rising standards of living. The historical experience of Barbados and Antigua, which reached replacement-level fertility in the 1980s, suggests that West Indian fertility declines reflect structural changes in national economies that created job opportunities for women. Family planning programs need to be evaluated with reference to the distinctive health and human rights goals other than fertility transition that they can effectively reach.

Adult↗

PubMed1991

Fertility decline in Taiwan: a study using parity progression ratios.

Taiwan's decline in fertility is studied by using period parity progression ratios. Levels of marriage and motherhood are found to have been high and essentially constant though the late 1980s, suggesting that the decline has been due almost entirely to declines in second and higher order-births. Families with three or more children play an important role in maintaining the current level of fertility. The level of fertility would be even lower without these families. They contributed more than one-half child per woman to the total fertility rate during most of the 1980s. Total fertility rates computed from the period parity progression ratios indicate a substantially higher level of fertility than the conventional total fertility rate; they remained above or at replacement level through 1988. A formal demographic analysis suggests that the conventional total fertility rate has been depressed by shifts in age at childbearing.

Adult↗

PubMedDate not supplied

An examination of factors influencing black fertility decline in the Mississippi Delta, 1880-1930.

Although the fertility decline in the black population in the Mississippi Delta between the late 1870's and early 1930's closely paralleled that of the national black population, it rose much more dramatically in the 1940's and 1950's to almost 1880 levels. Given the especially rural and oppressed conditions of blacks there, the initial decline seems puzzling. Low fertility rates in the 1930's reflected a large proportion of childless females. Investigations of changing contraceptive usage and mate exposure suggest both were minor components at most. Several physiological impairments were investigated including dietary deficiences, malaria, tuberculosis, and sexually transmitted diseases (STD). Evidence suggests STD played the major role, facilitated by nutritional and other health problems. Models relying heavily on those developed by McFalls and McFalls (1984) suggest 50-80 percent of the decline could have been due to the spread of STD. Age-specific birth rates for different periods and post-World-War-II fertility increases seem consistent with this finding.

Adolescent↗

PubMed1975

Emigration and fertility decline: the case of Barbados.

This paper examines the role of emigration in the recent fertility declines which have occurred on the island of Barbados. Barbados with a history of over two centuries of out-migration has experienced in the period 1951-1970 very significant migration loss. In the period 1960-1970 and up to the present fertility has been declining. An important question is what part has this net migration loss of 32,600 had on the reduction of the crude birth rate from 33.6 in 1960 or from 31.5 in 1956 to 20.5 in 1970? Using officially published net migration loss figures and supplementing them with data on Barbadians living overseas, we calculated the crude birth rates which would have occurred had there been no migration loss. We also calculated the numbers of births to be expected if certain age-specific fertility rates were maintained and compared these with the births to residents plus the calculated births to Barbadians overseas. We conclude that in both cases emigration is a very significant contributor to the fertility declines which have occurred and are still underway.

Adolescent↗

PubMed1998

Negotiating reproduction and gender during the fertility decline in Turkey.

This paper is concerned with the cultural construction of reproduction and gender in Turkey as it relates to the remarkable decline from high levels of fertility to near-replacement levels. It critiques demographic transition theory and family systems theory as found in the Turkish demographic discourse. A combination of ethnographic and demographic methodologies are used. The ethnographies are from working-class communities in Istanbul. A concept of negotiated conduct is used to interpret family dynamics in matters of reproductive control replacing the family systems models that are based on the assumption of male domination or patriarchy. It is found that the physical characteristics (male or female) of methods of contraception do not directly reveal whose power dominates negotiations. The variety of experience shows that not only women, but also men, negotiate in favor of birth control or, in some instances, to birth more children. The changes in structural conditions that brought fertility from high levels to near-replacement levels in Turkey were effective without very much "empowerment" of women. The proposition that women's status, in terms of education and economic activity, must improve to bring about a fertility decline is questioned by the Turkish experience.

Anthropology, Cultural↗

PubMed1993

The determinants of early fertility decline in Texas.

This study examines the determinants of fertility control in a frontier population made up largely of German-Americans during the years from 1850 to 1910. The analysis employs a complex register of population constructed from census enumerations, civil and ecclesiastical vital registration, and tax assessment rolls. The article begins with a series of bivariate analyses with cohort of mother's birth, religion, ethnicity, and husband's occupation determining marital fertility. The second half of the paper presents a multivariate model of the determinants of fertility using these and other demographic characteristics as independent variables. The conclusions emphasize the importance of the overall trend toward fertility decline in the United States, as well as the role of religion and of occupational differences, in determining changes in fertility behavior in the population of Gillespie County, Texas.

Acculturation↗

PubMedDate not supplied

The U.S. fertility decline, 1961-1975: the contribution of changes in marital status and marital fertility.

Changes in marital fertility have accounted for 83 percent of the decline in total fertility since 1971; changes in marital status accounted for 19 percent, and changes in nonmarital fertility had only a negligible effect. Declines in the level of marital fertility account for a substantial part of the overall decrease; postponement of childbearing did not occur in any significant degree until the 1970s.

Adolescent↗

PubMed1977

Fertility decline in Barbados: some spatial considerations.

Despite its small size, Barbados exhibits some striking regional differences in fertility levels, which persisted during a period of major fertility decline in the 1960s. Regression analyses are performed for 28 subregions, using sex ratio, male occupational structure, female education, and female employment for 1960 and 1970 as the independent variables. The spatial influence of the Barbados family planning program is also considered. The author argues that a concentration of family planning programs in areas of greatest accessibility and modernization contributes to spatial variations in fertility.

Adolescent↗

PubMed1991

Sex and respectability in an age of fertility decline: a Sicilian case study.

The paper examines two aspects of coitus interruptus as a sexual practice: (1) how, in the age of fertility decline in Western Europe, its meaning was reinterpreted from an earlier theological view that condemned it as licentious to a nineteenth century view that emphasized restraint, and (2) how it was actually experienced by a socially stratified birth-controlling population in rural Sicily, ca 1900-1970. The sequential experiences of gentry, artisans, and peasants in the Sicilian case study of transition from high to low fertility are consistent with late twentieth-century interpretations of coitus interruptus by Foucault and others as sexually restraining yet empowering. In each group, adoption of the practice enhanced access to respectability in a context of cultural and economic change. Moreover, those who adopted the practice increasingly stigmatized married couples with high birth parities as overly dominated by their sexual instincts and unworthy of respect.

Coitus Interruptus↗

PubMed1994

Fertility decline in Tanzania.

According to the 1991/92 Tanzania Demographic and Health Survey, a Tanzanian woman has, on average, 6.1 births before she reaches age 50, a decline of about one birth per woman since the early 1980s. The major proximate determinant of fertility is universal and prolonged breast-feeding. An analysis of the social and demographic correlates of fertility shows that infant and child mortality, level of education and age at first marriage are among the factors which significantly influence fertility in Tanzania.

Adolescent↗