Development and childlessness in the states and territories of Brazil

Abstract

This article provides an analytical account of the variability in and correlates of Brazil's childlessness rates. Following from the socioeconomic development model, which suggests that involuntary childlessness predominates among developing countries and voluntary childlessness among developed countries, this paper examines the extent to which levels of development are related to age‐specific rates of childlessness in the states and territories of Brazil. We find both variation within the age‐specific childlessness rates and important associations between measures of economic development in 1970 and the rates of childlessness in 1980. Moreover, childlessness in Brazil tends to be more voluntary than involuntary, particularly among the younger women in the more modernized subregions of the country.     

Trends in childlessness in the United States, 1910–1975

Abstract

This paper examines trends in childlessness for ever‐married women in the United States. Data assembled from assorted census materials permit cohort and period investigations for a number of time periods, from 1910 to 1975, for various color and ethnic groups. Whether examined at the period or cohort level, the incidences in percentage rates of childlessness have varied irregularly over time. We focus particularly on the younger cohorts of white women (those beginning fecundity after 1965); they show higher rates of childlessness at each age than any of the older cohorts at similar ages in the reproductive cycle. We suggest that a major portion of the increasing rates of these younger cohorts may be attributed to increases in voluntary childlessness, which in turn may be linked to broader changes in the fabric of society regarding fertility control, contraceptive technology, female work preferences and patterns, and sexual and family norms.     

Becoming voluntarily childless: An exploratory study in a Scottish city

Abstract

This paper looks at motives that inform the decision to remain voluntarily childless. It is assumed that voluntary childlessness is not a pathological condition nor is it determined by specific social situations. Situations provide the context within which motives emerge, in the case of voluntary childlessness providing individuals or couples with the opportunity to consider unconventional interpretations of family life that may eventually lead to its rejection. Individuals who become childless prior to finding a “partner” tend to come from families which deviated from the nuclear ideal and to reject parenthood. Those whose decision emerges after a “partnership” has been formed tend to have created alternative life styles and wish to protect the advantages of living without children. It is tentatively concluded that the proportion of couples remaining childless will increase.     

Modernization and childlessness among the governorates of the Arab Republic of Egypt, 1976

This paper examines the degree to which childlessness is influenced by levels of modernization among the governorates of the Arab Republic of Egypt. The data have been derived mainly from the 1976 Population and Housing Census of the Arab Republic of Egypt. The childlessness rates used are based on census data on number of children born to married women. In 1976, the higher the levels of modernization, the lower the rates of childlessness among women aged 30 and over, and the higher the rates of childlessness among women aged 20-30. The lower rates are found in and around Cairo, and some of the governorates with higher rates are in Upper Egypt. Of the 25 governorates, Suez has the lowest childlessness rate. To some degree, the patterns of childlessness may be affected by changing patterns in age-specific 1st marriage rates. The childlessness rates for the younger women in the Egyptian governorates are associated with some of the modernization variables. The findings suggest that childlessness among women aged 30 and older is mostly involuntary, but that for younger women it is partly voluntary. Increases in modernization among the Egyptian governorates should, therfore, result in net increases in rates of childlessness and net decreases in fertility. There are at least 3 statistically independent sources of variation in modernization which characterize the governorates of Egypt: factors that reflect structural development, female status, and health personnel.     

A period analysis of parity distribution among white and nonwhite women in the United States, 1940–1974

Abstract

The historical trends of childlessness and of one‐child, two‐child, and three‐or‐more‐child families among white and nonwhite women in the United States are studied in terms of period fertility tables. Given the age and parity of a woman, we can read from the fertility tables how her parity is expected to change at successive ages during the rest of her childbearing period, if she is subjected to the age‐parity‐specific fertility rates for a particular year. The fertility tables for white and nonwhite women are constructed for the years 1940, 19S0, 1960, 1970, and 1974. These tables show that among white women who have completed their childbearing (with period rates), the percentage with more than two children has decreased from 66 in 1960 to 27 in 1974, whereas the corresponding reduction among nonwhite women is from 67 to 48 per cent (Table 1, Case 1).     

Structural determinants of childlessness: A nonrecursive analysis of 1970 U.S. rates

Abstract

This study tests two theories accounting for observed relationships between U.S. rates of childlessness and sociodemographic characteristics using data on Black and white women aged 30–44 from the 1970 U.S. census. Traditional theory sees the observed correlations as spuriously caused by involuntary sterility, while voluntaristic theory interprets the associations as evidence of influences on the decisions of fecund couples to remain childless. We examine the two positions by estimating and then comparing the aggregate causal structures of childless rates and cumulative fertility rates of women with proven fecundity. The traditional approach expects little if any relationship, while the voluntaristic approach predicts high similarity between the two estimated structures. Results support the voluntaristic position and thus offer indirect substantiation of the voluntaristic theory of areal variation in childless rates.     

Factors in the incidence of childlessness in Canada: an analysis of census data

Due to the difficulties involved in attempting to determine the relative proportion of involuntary childlessness and of voluntary childlessness in a given population, many investigators insist that the problem can only be examined in small-scale studies using intensive psychological interviewing techniques. A method for assessing the causes of childlessness in a population using census materials is described. If a distinction is made between psychological and physiological causes, instead of between intentional and unintentional causes, it is possible to assess the relative importance of these causes using large-scale investigation techniques. Physiological causes include all physiological conditions which produce sterility. Psychological causes include both psychosomatic infertility and the voluntary decision not to have children. The method involves using the minimum rate of childlessness in a population group known to place a high value on fertility as an estimate of the rate of physiological childlessness in the population. This estimate is then subtracted from the childlessness rate observed in other population groups in the same society in order to determine the degree of psychological childlessness in these other population groups. This method was used to assess the causes of childlessness in Canada. Census materials were used to determine the minimum rate of childlessness among rural women in Quebec. Since this group is primarily Catholic and places a high value on children, its childlessness rate provides an estimate of the proportion of sterile couples in the population. This rate was then subtracted from the childlessness rates for urban Canadian women, and the remainder provided an estimate of psychological childlessness among urban women. Age of marriage was controlled for since rural women married at younger ages. Study findings were 1) the proportion of childlessness among urban women declined over the years as 15.2% of the women over 45 years old were childless while only 10.8% of the women, aged 30-44, were childless; 2) the proportion of physiological childlessness declined from 6.6% among women over 45 years old to 4.6% among women, aged 30-44; and 3) approximately 50% of the cases of childlessness among urban women were due to psychological factors. These findings do not support the contentions of some investigators that 10% of the population is sterile and that psychological childlessness is rare. Study findings were presented in tabular form.     

Voluntary Childlessness Among American Men and Women in the Late 1980's

Abstract

Most studies of childlessness in the United States have relied on unrepresentative, opportunistic samples collected in a variety of ways. Thus, the relationship of various correlates to childlessness is not well known. Some studies have focused on demographic variables, but have not examined attitudinal factors associated with childlessness—something the opportunistic samples have been able to do. In this paper we examine both attitudinal and demographic factors associated with childlessness in the United States. The data used in this paper are from the National Survey of Families and Households collected in 1987 and 1988. The data set includes both demographic data, perceived advantages and disadvantages of having children, and attitudinal data about related social issues. Overall, the rate of voluntary childlessness was not high. Only 3.5 per cent of the men and 2.8 per cent of the women reported that they were childless and did not expect to have children. Only one category of people (unmarried men and women over the age of 35) had rates that exceeded ten per cent. A combined variable of age and marital status was the best predictor of childlessness. A scale of reasons or justifications for having children was the next best predictor. In addition, attendance at religious services, number of hours the respondents desired to work and education (for women only) were related to childlessness. Those who scored highly on measures of support for traditional families and support of extended families also tended to have lower rates of childlessness. Occupational status, religious denomination, and race, on the other hand, were not significantly related to childlessness. Measures of gender equality, religious fundamentalism, and support for mothers working were also not related to childlessness.     

Case-control study of whether subfertility in men is familial.

OBJECTIVE--To test the hypothesis that subfertility in men is familial and to examine the distribution of subfertility within families for consistency with a genetic cause. DESIGN--Case-control study and segregation analysis. SETTING--Two teaching hospitals in Leeds. SUBJECTS--Cases (probands) were men with an abnormal sperm count who attended a subfertility clinic and whose partners had no major factor contravening fertility. Controls were fathers of two or more children recruited through vasectomy clinics or a maternity department. MAIN OUTCOME MEASURES--The incidence of involuntary childlessness among brothers with partners and among sisters and second and third degree male relatives. When possible clinical and laboratory details were obtained from involuntarily childless brothers. RESULTS--Seventeen of the 148 (11.5%) brothers of probands but none of the 169 brothers of controls had sought medical advice for childlessness (P < 0.0005). Four probands had more than one involuntarily childless brother. There were six further brothers whose childlessness was thought to be involuntary bringing the total prevalence of subfertility among brothers of probands to 16%. Segregation analysis was consistent with an autosomal recessive mode of inheritance accounting for 60% of subfertility in men. Seventeen of the 346 (4.9%) uncles of probands and 10 of 420 (2.8%) uncles of controls were reported to be involuntarily childless (P = 0.09), but there was no difference in childlessness among sisters. In three families sperm counts from "affected" brothers confirmed the diagnosis and showed considerable similarities within but not between families. CONCLUSION--Subfertility in men has a familial component, and the observations are consistent with an autosomal recessive mode of inheritance in over half the cases. Several different genes are probably involved.     

Infertile or childless by choice? A multipractice survey of women aged 35 and 50.

Eleven general practitioners examined the medical records of all women on their lists born in 1950 (617 patients) and 1935 (533 patients) to determine the prevalence of childlessness and specialist consultations about infertility. Eighty eight (14.3%) of the women born in 1950 and 41 (7.7%) of those born in 1935 were childless. Sixty eight women born in 1950 (11.0%) and 17 born in 1935 (3.2%) were considered childless by choice. Involuntary childlessness was found in 20 (3.3%) of the women born in 1950 and 24 (4.5%) born in 1935. Forty two (6.8%) of the women born in 1950 had consulted a specialist about infertility as compared with 19 (3.6%) born in 1935. This study found a significant increase in voluntary childlessness among the younger women; there was no evidence of a change in the prevalence of involuntary childlessness despite the increasing demand for specialist referral, which appeared to be made by women who were parous or destined to become so.     

Childlessness among American women

Abstract

The rate of childlessness in the United States has increased over the last two decades. Changing or differential rates by different segments of society have important implications for society. Most previous studies have relied on unrepresentative opportunistic samples to identify those segments of society with lower or higher rates of childlessness. These types of samples may misestimate both the number of women planning to remain childless and the magnitude of the correlates of childlessness. The present study uses these previous studies to identify predictor variables, but tests their significance using a recent national representative sample of women in the United States, aged 20–44: Cycle III of the National Survey for Family Growth, collected in 1982. The most important demographic factors are marital status and fecundity status, followed by age, race or ethnicity, education of the respondent, labor force status, and region. Father's education and mother's education are slightly, but not significantly, related to childlessness. Contrary to findings from less representative samples, urban‐rural differences and religion are not related to childlessness.     

Natural selection and degenerative cardiovascular disease

Abstract

The analyses shown here indicate that the pervasiveness of fertility trends found earlier for the 1950's and 1960's has continued for the 1970's. The national period fertility trends have occurred within every racial, social, and economic subgroup examined. As before, there is no evidence of a narrowing of fertility differentials within successive cross‐sections. Variables, such as race or education, continue to exert effects on cross‐sectional fertility differences. Standard socioeconomic variables operate to shift the entire trend line up or down, but do not explain the trend line. The question remains of what causes changes in period fertility rates in developed societies.     

Fostering repeat donations in Ghana

IntroductionMost African countries are challenged in recruiting and retaining voluntary blood donors by cost and other complexities and in establishing and implementing national blood policies. The availability of replacement donors who are a cheaper source of blood has not enhanced repeat voluntary donor initiatives.MethodsAn overview of activities for recruiting and retaining voluntary blood donors was carried out. Donor records from mobile sessions were reviewed from 2002 to 2008.Results and discussionA total of 71,701 blood donations; 45,515 (63.5%) being voluntary donations with 11,680 (25%) repeat donations were collected during the study period. Donations from schools and colleges contributed a steady 60% of total voluntary whilst radio station blood drives increased contribution from 10 to 27%. Though Muslim population is less than 20%, blood collection was above the 30-donation cost-effectiveness threshold with a repeat donation trend reaching 60%. In contrast Christian worshippers provided <25 unit/session and 30% repeat donations. Repeat donation trends amongst school donors and radio blood drives were 20% and 70% respectively.ConclusionRepeat donations rates have been variable amongst different blood donor groups in Kumasi, Ghana. The impact of community leaders in propagating altruism cannot be overemphasized. Programs aiming at motivating replacement donors to be repeat donors should be developed and assessed.     

High frequency vibration conditioning stimulation centrally reduces myoelectrical manifestation of fatigue in healthy subjects

ObjectiveVibration conditioning has been adopted as a tool to improve muscle force and reduce fatigue onset in various rehabilitation settings. This study was designed to asses if high frequency vibration can induce some conditioning effects detectable in surface EMG (sEMG) signal; and whether these effects are central or peripheral in origin.Design300 Hz vibration was applied for 30 min during 5 consecutive days, to the right biceps brachii muscle of 10 healthy males aged from 25 to 50 years. sEMG was recorded with a 16 electrode linear array placed on the skin overlying the vibrated muscle. The test protocol consisted of 30% and 60% maximal voluntary contraction (MVC) as well as involuntary (electrically elicited) contractions before and after treatment.ResultsNo statistically significant differences were found between PRE and POST vibration conditioning when involuntary stimulus-evoked contraction and 30% MVC were used. Significant differences in the initial values and rates of change of muscle fibre conduction velocity were found only at 60% MVC.Conclusions300 Hz vibration did not induce any peripheral changes as demonstrated by the lack of differences when fatigue was electrically induced. Differences were found only when the muscle was voluntarily fatigued at 60% MVC suggesting a modification in the centrally driven motor unit recruitment order, and interpreted as an adaptive response to the reiteration of the vibratory conditioning.     

Using voluntary motor commands to inhibit involuntary arm movements

A hallmark of voluntary motor control is the ability to stop an ongoing movement. Is voluntary motor inhibition a general neural mechanism that can be focused on any movement, including involuntary movements, or is it mere termination of a positive voluntary motor command? The involuntary arm lift, or ‘floating arm trick’, is a distinctive long-lasting reflex of the deltoid muscle. We investigated how a voluntary motor network inhibits this form of involuntary motor control. Transcranial magnetic stimulation of the motor cortex during the floating arm trick produced a silent period in the reflexively contracting deltoid muscle, followed by a rebound of muscle activity. This pattern suggests a persistent generator of involuntary motor commands. Instructions to bring the arm down voluntarily reduced activity of deltoid muscle. When this voluntary effort was withdrawn, the involuntary arm lift resumed. Further, voluntary motor inhibition produced a strange illusion of physical resistance to bringing the arm down, as if ongoing involuntarily generated commands were located in a ‘sensory blind-spot’, inaccessible to conscious perception. Our results suggest that voluntary motor inhibition may be a specific neural function, distinct from absence of positive voluntary motor commands.     

Family background, schooling and childlessness in Australia

Using data from Wave 1 of the Household Income and Labour Dynamics in Australia (HILDA) survey, this paper analyses the extent to which childlessness among Australian women aged 40-54 years varies according to the size and type of family in which they were brought up, and the level and type of schooling they had. Multilevel logistic analysis shows that having been educated in a non-government school, having stayed at school to year 12, having a small number of siblings, at age 14 having a father who was either dead or absent, at age 14 having a father who was employed in a professional occupation, or being a migrant from North or West Europe, North America, East Asia or South-East Asia, all are significantly associated with higher rates of childlessness among women in the 40-54 years age range. The effects of these early lifecourse variables on marital and socioeconomic status in later life, and hence on childlessness, are also considered. The implications of the findings for fertility trends and for Australia's public debate are discussed.     

Do high-status people really have fewer children?

Evolutionary discussions regarding the relationship between social status and fertility in the contemporary U.S. typically claim that the relationship is either negative or absent entirely. The published data on recent generations of Americans upon which such statements rest, however, are solid with respect to women but sparse and equivocal for men. In the current study, we investigate education and income in relation to age at first child, childlessness, and number of children for men and women in two samples—one of the general American population and one of graduates of an elite American university. We find that increased education is strongly associated with delayed childbearing in both sexes and is also moderately associated with decreased completed or near-completed fertility. Women in the general population with higher adult income have fewer children, but this relationship does not hold within all educational groups, including our sample with elite educations. Higher-income men, however, do not have fewer children in the general population and in fact have lower childlessness rates. Further, higher income in men is positively associated with fertility among our sample with elite educations as well as within the general population among those with college educations. Such findings undermine simple statements on the relationship between status and fertility.     

Response of external inspiration to the movements induced by transcutaneous spinal cord stimulation

The dynamic of the parameters of lung ventilation and gas exchange have been studied in 10 young male subjects during involuntary stepping movements induced by transcutaneous spinal cord electrical stimulation applied in the projection of T ₁₁–T ₁₂ vertebrae and during voluntary stepping movements. It has been found that the transcutaneous spinal cord stimulation inducing stepping movements leads to an increase in breathing frequency and a reduction in tidal volume. These effects may be mediated by some neurogenic factors associated with muscular activity during stepping movements, the activation of abdominal expiratory muscles, and the interaction between the stepping pattern and breathing generators.     

Maternal smoking and twinning.

In order to investigate a possible association between maternal smoking during pregnancy and twinning, information on 1,096,330 single births and 12,342 twin births in 1983-95 was obtained from the Swedish Medical Birth Registry (MBR). All odds ratios (OR) were estimated after stratification for year of birth and maternal age, parity, and educational level. Smoking women, compared with non-smoking women, were at increased risk of having dizygotic (DZ) twins, but the risk increase was only evident among multiparas. A strong association between previous involuntary childlessness and dizygotic (DZ) twinning (especially in primiparas) was found. The strongest association between maternal smoking and DZ twinning was found among multiparas without any history of involuntary childlessness (OR: 1.35, 95%CI:1.22-1.49), whereas among women who had experienced involuntary childlessness, the opposite was seen (OR: 0.82, 95%CI:0.66-1.00, no difference between parity strata). Weinberg's differential method was used to estimate the number of monozygotic (MZ) twins, and a method of estimating stratified ORs among mothers of MZ twins was presented. No association was found between MZ twinning and maternal smoking (OR: 0.96, 95%CI:0.86-1.07), and no confounding by parity or previous involuntary childlessness was indicated. Several non-causal explanations to the positive association between DZ twinning and maternal smoking among multiparas were discussed, but homogeneity over strata indicated that maternal smoking may be a true risk factor for double ovulation.     

Relation of fertility to occupational status,IQ, educational attainment,and size of family of origin: A follow‐up study of a male Kalamazoo public school population

Abstract

Drawing upon data from the 1965 National Fertility Study, this paper attempts to categorize white wives by their form of childlessness. Three categories of childlessness emerge: Voluntary, Involuntary, and Temporary. The three types of childless wives are compared across a number of demographic, socioeconomic, marital, and religious characteristics. The Voluntarily and Involuntarily Childless wives are remarkably similar on most characteristics, and they differ significantly from the Temporarily Childless.