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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: Fertility is affected in ulcerative colitis after surgery and in active Crohn's disease, and most medications for IBD are safe during pregnancy and breastfeeding, with notable exceptions.

137 citations

Journal ArticleDOI
TL;DR: A detailed discussion of early demand for fertility control among different racial groups and government intervention in its impact can be found in this paper, where the relevance of the South African experiences to other parts of Africa and the implications of democratization efforts and majority Black rule are discussed.
Abstract: There is some evidence to suggest that Black South African started to decline in 1960 which was earlier than anywhere else in Black Africa. The Black South African population is larger than any Black population in Africa with the exception of Nigeria Ethiopia and Zaire. The national population program was an Asian-type program distinguished by expenditures and services not evident elsewhere in Africa. Clinical family planning (FP) services were densely located to provide better coverage than is available anywhere in the world. Contraceptive prevalence was around 60% for women overall and 50% for Black women in the 1990s. The FP program difference was in its lack of ability to mobilize the whole community. A lengthy discussion is provided of the early (pre-1963) demand for fertility control among different racial groups government intervention in its impact the relevance of the South African experiences to other parts of Africa and the implications of democratization efforts and majority Black rule. The Black population lives in an urban industrialized economy with an income level among the highest of African countries. Primary schooling is universal and 60% attend secondary school. Fertility data on the Black population are available from the fertility survey in 1974 and 1987-88. From these and other studies it appears that the White population followed a pattern similar to the Western model. Africaner fertility was higher than White fertility until about the 1960s and then followed a similar pattern. Indian Colored and Black women had a constant fertility of 6-7. Colored fertility began to decline after 1960 Indian after 1940 and Blacks in the 1970s and 1980s to rapidly reach 4.6 in 1989. The exact level of Black fertility is still somewhat in doubt. Population policy is demarcated by periods before 1963. 1963-74 (government intervention) 1974-83 (National FP Program) and from 1984 (the Population Development Program). Experience indicates that once there is demand for fertility control a FP program can lead to a decline in fertility but a fragile demand limits even the best FP program. Sociocultural resistance is stronger than that encountered in Asia and democratization and the political position of the African National Congress will bring about a reduction in funding but a broader popular identification for the FP program. As socioeconomic opportunities for Blacks increase it is likely that fertility will continue to fall.

137 citations

Journal ArticleDOI
TL;DR: This article found that the relationship between successive generations is becoming stronger with time, and that it is now of a comparable order of magnitude to widely-used conventional covariates such as educational level.
Abstract: A number of studies of populations in earlier generations haveshown that fertility patterns of parents and children arepositively correlated, although the relationship is frequentlydesignated as `weak'. Models that may be used to investigate theways in which patterns of demographic behaviour persist betweengenerations are considered. The principal frameworks used arefitting of simulation and multi-level models. The data sourcesutilised are the 1986 ISSP co-ordinated series of surveys onsocial networks, the country files for Italy, Norway and Polandfrom the UNECE co-ordinated FFS programme, and the US NationalSurvey of Families and Households which contains particularlyrich information on the experience of demographic events acrossdifferent generations. We find that the relationship betweenfertility of successive generations is becoming stronger withtime, and that it is now of a comparable order of magnitude towidely-used conventional covariates such as educational level. This intergenerational relationship cannot be explained bydifferential fertility across socio-economic groups. Reasons whythe strength of the relationship has been understated and theimplications of results from such analyses are discussed.

137 citations

Journal ArticleDOI
TL;DR: Sockeye salmon Oncorhynchus nerka sperm maintained high fertility for 10 s after being exposed to water but fertility dropped sharply after that and eggs showed limited longevity after being immersed in water, with a large drop in fertility occurring after 20 s of exposure to water.
Abstract: Sockeye salmon Oncorhynchus nerka sperm maintained high fertility for 10 s after being exposed to water but fertility dropped sharply after that Eggs also showed limited longevity after being immersed in water, with a large drop in fertility occurring after 20 s of exposure to water The association between eggs and sperm occurs very rapidly 80% fertilization success was achieved with 5 s of sperm-egg mixing and c 25% was achieved with <05 s of sperm-egg mixing Sperm from different male age classes differed little in motility and did not differ at all in their propensity to fertilize eggs The results have important implications for mate choice and sperm competition

137 citations

Journal ArticleDOI
TL;DR: In this paper, the authors compare the declines in fertility in Europe and the Third World and conclude that lower levels of fertility were largely due to the adoption of innovative behavior within marriage.
Abstract: This article compares the declines in fertility in Europe and the Third World. Lower levels of fertility were largely due to the adoption of innovative behavior within marriage. So far this transformation of reproduction has been monotonic and rapid. Socioeconomic development is associated with the timing of the onset of the transition and is responsible for differences among groups during the transition, although it is not yet possible to rule out alternative explanations such as ideational or institutional change. The pace and pervasiveness of the declines, however, suggest that a mechanism of diffusion is involved.

137 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