Fertility

About: Fertility is a research topic. Over the lifetime, 29988 publications have been published within this topic receiving 681106 citations.

Family limitation in pre-industrial England.

Abstract: Data on baptisms marriages and burials obtained from the parish registers of Colyton in east Devon England from 1538-1837 were used to identify fertility changes in the parish during that period. The Henry method of family reconstitution was applied to the data. The Colyton register was uninterrupted from 1538-1837 but the degree of detailed information contained in the records varied at different times. These differences were examined from a methodological point of view to determine the amount of information required for applying the family reconstitution method. Analysis of the data revealed that from 1550-1645 the birth rate was high compared to the death rate. From 1645-1730 the birth rate was low in comparison to the death rate and the population of Colyton declined. From 1730-1785 there was a balance between birth and death rates and from 1780-1837 births exceeded deaths. Changes in the mean age at marriage explained some but not all of the fluctuations in the birth rate. A comparison of data for the high marital fertility period of 1560-1629 with data from the low marital fertility period of 1645-1720 revealed evidence that the inhabitants of Colyton were practicing birth control during the later period. Mean birth intervals for the 1st-4th births were 27.5 months for the earlier period and 31.4 months for the later period. There were more childless marriages in the later period thanin the earlier period. From 1645-1720 among women aged 30-34 those who married after the age of 30 had a higher fertility rate than those who married before they were 30 years old. The conclusion was reached that societies worked out different types of equilibriums between population size and resources. Some socieities as posited by Malthus produce they maximum number of people and they minimize the amount of resources available for each individual. Other societies such as the community of Colyton minimize population size and maximize resource allocations to their members.

The bases of paleodemography

Abstract: Accurate identification of every skeleton (age, sex, health, female fecundity) in a fully sampled cemetery provides data on adult longevity, infant and child death ratios, sex ratio, fertility and birth, death, and natural increase rates, population density, family structure and microevolutionary selection.

Advanced paternal age: How old is too old?

Abstract: Average paternal age in the UK is increasing. The public health implications of this trend have not been widely anticipated or debated. This commentary aims to contribute to such a debate. Accumulated chromosomal aberrations and mutations occurring during the maturation of male germ cells are thought to be responsible for the increased risk of certain conditions with older fathers. Growing evidence shows that the offspring of older fathers have reduced fertility and an increased risk of birth defects, some cancers, and schizophrenia. Adverse health outcomes should be weighed up against advantages for children born to older parents, mindful that these societal advantages are likely to change over time.

Personal and environmental characteristics related to epithelial ovarian cancer. I. Reproductive and menstrual events and oral contraceptive use.

Abstract: In two case-control studies conducted in the six-county San Francisco Bay Area, 111 women diagnosed with epithelial ovarian carcinoma in 1974-1977 and 188 women diagnosed in 1983-1985 were interviewed concerning their menstrual, sexual, and reproductive histories. For comparison, interviews were conducted with 752 control women admitted to the same hospitals within six months of the cases; for cases diagnosed in the later period, interviews were also conducted with an additional 259 population-based controls selected by random digit dialing. Controls were matched to cases by age and race. Qualitative and quantitative findings were similar for the two studies. In the combined data, cases were more likely than their matched controls to have been nulliparous, to have undergone menarche at an early age, and to have refrained from using oral contraceptives. Menopause occurred slightly later for cases than for controls, but the differences were not statistically significant. Neither age at first term pregnancy (20 or more weeks gestation) nor number of term pregnancies was predictive of ovarian cancer risk. The protection afforded by oral contraceptive use was independent of parity, and it increased with increasing duration of use. There were no trends in risk with time since last oral contraceptive use or with time since first use, after adjustment for duration of use. These observations suggest that oral contraceptive use decreases risk for ovarian cancer, rather than merely indicates fertility, which may itself decrease risk of developing the disease. The authors combined reproductive characteristics and oral contraceptive use to estimate a woman's total duration of ovulation, which was positively associated with ovarian cancer risk (p less than 0.001 for trend). These observations support the concept that the greater the duration of ovulation or accompanying endocrinologic phenomena, the greater a woman's risk for ovarian cancer.