Completed Family Size Research Articles

Time trends and determinants of completed family size in a rural community from the Basque area of Spain (1800-1969).

The focus of this work is the analysis of changes in completed family size and possible determinants of that size over time, in an attempt to characterize the evolution of reproductive patterns during the demographic transition. With this purpose in mind, time trends are studied in relation to the mean number of live births per family (as an indirect measure of fertility), using family reconstitution techniques to trace the reproductive history of each married woman. The population surveyed is a Spanish rural community called Lanciego, located at the southern end of the province of Alava (Basque Country). A total of 24,510 parish records of baptisms, marriages and burials made between 1800 and 1969 were examined to obtain the demographic data set. For each reconstituted family, the variables included in the study were the number of live births per family or family size (FAMS), year of marriage (YEAR), age at marriage of both partners (AMAN, AWOM), wife's age at the end of marriage (WEND), duration of marriage (MARD), age at first maternity (A1CH), length of reproductive span (REPS) and number of children dying before their first anniversary (MINF). Through a principal component analysis, three factors were found that explained more than 75% of the total variance. Association of variables in factors I and III was particularly useful in characterizing the variability of mean family size in pre-transitional, transitional and post-transitional cohorts. During demographic transition, a decreasing trend is observed in the variables FAMS, REPS and MINF, while variables AWOM, AMAN, WEND and A1CH show a tendency to increase over the 20th century. Results obtained by multiple regression analysis confirm that the best predictors of family size (dependent variable) were REPS and MINF, which between them explained over 85% of the total variation in FAMS (R2 = 0.853). In Lanciego, birth control seems to be present on the evidence of an increase in age at first maternity and a decrease in age at last parturition, indicating that the beginning of the reproductive span is delayed and its end is brought forward. Interaction between family size and infant mortality is discussed in the light of various hypotheses, including replacement of descendants, the so-called biological effect and the theory of r and k selection.

How well do desired fertility measures for wives and husbands predict subsequent fertility? evidence from Malaysia

Data on fertility preferences are often used to help predict future fertility and the demand for contraception. The quality of fertility preference data is of prime importance when examining how well stated fertility preferences predict subsequent births and completed family size, and how well they predict fertility-related behaviour such as contraceptive use. Data on fertility preferences have also been used to construct measures of the unmet need for contraception and of unwanted fertility. The usefulness of these measures, which have been the basis for many studies and some programmatic efforts, depend on the underlying component (stated fertility preferences) being valid and reliable.

Correlates of women’s preferences for treatment of heavy menstrual bleeding

This cross-sectional survey investigated factors associated with treatment preferences of women with menorrhagia. Women ( n=474) aged 35–54 years referred to gynaecology out-patient clinics for menorrhagia were mailed a self-administered questionnaire before their first clinic visit. The main outcome measure was treatment preference. Hysterectomy and conservative treatment (combined with no treatment) were favoured equally often. In a multivariate analysis, completed family size ( P=0.003), menstrual pain ( P=0.02), irregular periods ( P=0.03), and higher age ( P=0.04) predicted hysterectomy preference, as did lower education level ( P=0.001), gynaecologist consultations ( P=0.002), and unemployment ( P=0.03). The psychological factors assessed were not associated with treatment preference. In conclusion, rational considerations regarding stage of reproductive life and severity of symptoms were linked to women’s treatment preferences. However, education, employment status and use of specialists’ services guided women’s preferences even more powerfully than menstrual symptoms and burden caused by them. Doctors should pay more attention to motivating women for a trial of conservative treatment since only half of the women reported previous treatment for their menstrual problem.

Demographic consequences of unpredictability in fertility outcomes

Child survival is probabilistic, but the unpredictability in family formation and completed family size has been neglected in the fertility literature. In many societies, ending the family cycle with too few or too many surviving offspring entails serious social, economic, or fitness consequences. A model of risk- (or variance-) sensitive adaptive behavior that addresses long-term fertility outcomes is presented. The model shows that under conditions likely to be common, optimal, risk-sensitive reproductive strategies deviate systematically from the completed family size that would be expected if reproductive outcome is were predictable. This is termed the "variance compensation hypothesis." Variance compensation may be either positive or negative, resulting in augmented or diminished fertility. Which outcome obtained is a function of identifiable social, economic, and environmental factors. Through its effect on fertility behavior, variance compensation has a direct bearing on birth spacing and completed fertility, and thereby on problems in demography and human population biology ranging from demographic transitions to maternal depletion and child health. Risk-sensitive models will be a necessary component of a general theory of fertility.

Fertility Decline in Former “Asian Tigers”

The fertility opportunity hypothesis suggests that individuals and couples adjust family size in response to their perception that economic opportunity is increasing (or diminishing.) A sense that opportunities are expanding encourages a relatively high, even rising, family size target. On the contrary, the perception that opportunities and resources will fall short of satisfying the aspirations of oneself or family lead to lowering family size targets. The literature suggests that family size target translates into completed family size on the order of 85 to 90 percent. The economic collapse of former “Asian tigers” in late summer, 1997, offered a chance to test the hypothesis prospectively. In, 1998, an author (Abernethy) predicted that fertility rates in the nine Asian tiger economies would fall during the 1997-1999 interval at a faster rate than had been observed in immediately preceding two-year intervals. This paper reports the results of tests of the hypothesis with respect to the Asian tigers and several other country clusters for which no particular prediction was made. Preliminary findings appear to support the fertility opportunity hypothesis.

On the impossibility of inferring cohort fertility measures from period fertility measures

A particularly important struggle faced by demographic analysts is, how to arrive at statements about family formation processes from a cohort perspective from data that are essentially collected on an annual basis. The present paper is concerned with this struggle, mostly restricted to the case of fertility. The central question investigated here is: given observed period data, what can we conclude about the completed family size of real women? I review several existing methods to infer cohort fertility from period fertility measures. The conclusion is that, for each method, its justifiability can be verified only empirically: by looking at cohort fertility directly. To illustrate how this can be done, the paper analyses fertility data from a cohort perspective for two countries, Italy and the Netherlands.

Is There a Stabilizing Selection Around Average Fertility in Modern Human Populations?

Possibly the greatest challenge for an evolutionary explanation of demographic transition is the fact that fertility levels universally start to fall first among the well‐to‐do, well‐educated, healthy classes, which can be explained only by some voluntary or at least adaptive action. The problem of how restraints on fertility could have evolved by natural selection has been tackled with group selection models as well as with stabilizing selection models. The latter model, which is critically discussed in this article, posits that some intermediate (rather than maximal) level of fertility is optimal for long‐term reproductive success. Tests of stabilizing selection in human populations are rare, their results inconclusive. Here four sets of data are analyzed: they are samples drawn from the 'class of 1950 of the US Military Academy at West Point (cohorts 1923–29), retired US noncommissioned officers (cohorts 1913–37), and western German and eastern German physicians (cohorts 1930–35), all containing fertility data over two generations, and from European royalty (cohorts 1790–1939) containing fertility data over four generations. Deterministic as well as stochastic fitness measures are used. It is found that maximal, not average, fertility in the first generation leads to maximal long‐term reproductive success. Also against prediction, no decreasing marginal fitness gains by increasing fertility can be observed. The findings leave little space for considering stabilizing selection as a plausible mechanism explaining the course of demographic transition but indicate instead that biological evolution today is as fast and vigorous as ever in human history. Even in large populations, all people living today may be the descendants of just some few percents—a much smaller proportion than generally believed— of the people living some generations ago.

Female sterilisation through mini-laparotomy at Gondar College of Medical Sciences.

To describe the socio-demographic characteristics and clinical course and follow up of clients who have undergone voluntary surgical contraception (VSC) through minilaparotomy (mini-lap) under local anaesthesia (LA). Also, to evaluate the safety and method satisfaction, so as to forward recommendations for method utilisation in the Ethiopian context. A case series design where pre- and post-operative conditions of clients coming for voluntary surgical contraception via mini-laparotomy were systematically analysed. Department of Obstetrics and Gynaecology, Gondar College of Medical Sciences, Gondar, Ethiopia. Eighty two clients (median age of 33 years, range 25-40) who decided to use tubal sterilisation method of contraception from April 1993 to May 1995 were included in the study. A format prepared and distributed to VSC providing sites in Ethiopia by the Family Guidance Association of Ethiopia (FGAE) was used in collecting the necessary information, including informed consent of every client. Previous knowledge of contraceptive methods, decision making for tubal sterilisation, size of incision, advantages of use of local anaesthesia in the local setting, duration of hospital stay, conditions on follow up. Eighty two (55.4%) women underwent tubal sterilisation through mini-lap. The mean number of the live children per client was 6.2 +/- 1.7, with parity ranging from two to eleven children. Mothers with five or more children were 70 (85.4%). Among 69 mothers (84.1%), the last pregnancy outcome were live births. The average length of the time since making a decision not to have any more children was 2.5 +/- 2 years (median of one year). The rationales given were economic, ill health and completed family size. Regarding the pattern of decision making, in 77 (91.9%) clients both the couples were involved in decision making. All except two underwent the procedure under LA and no complication was encountered during surgery. Follow-up attendance was 100% in one-year period and nothing serious was reported. All reported to be satisfied with the method. The study showed that early decision making by involving both couples other than proper case selection minimises regrets. The authors believe that tubal sterilisation through mini-lap under LA is an ideal method in developing countries where access to family planning and other reproductive health services are not widely available and where there is population explosion, less than 10% contraceptive prevalence rate and high maternal mortality.

Natural Fertility in Northeastern Mexico

Background The aims of this study were as follows: 1) to describe the fertility of a sample of Mexican women (≥45 years of age, married, not using any family planning methods, and residing in the Mexican state of Nuevo León); 2) to determine whether or not the distribution of completed family size fits the negative binomial distribution, as in other populations studied in the world, and 3) to assess the association between fertility and 10 explanatory variables. Methods A sample of 410 women was interviewed at and selected from seven medical units of the Instituto Mexicano del Seguro Social (IMSS). The women were grouped by their year of birth (1896–1925 and 1926–1955) and birthplace [persons whose four grandparents were born in northeastern Mexico (NE) and outside northeastern Mexico (Not-NE)]. A binomial negative distribution analysis was assessed. Multiple linear regression was used to assess association between fertility (transformed by the use of inverse hyperbolic sines) and 10 explanatory variables, including age at marriage, heterozygosity, individual admixture, wife's education, husband's education, wife's occupation, husband's occupation, and couple's residence zone, birth year, and birthplace. Results Completed fertility was only associated with age at marriage. This population showed a fertility pattern similar to those described in Venezuelan and Brazilian populations in 1950 and 1940, respectively. Conclusions We conclude that before worldwide family planning programs, fertility was determined mainly by natural selection forces.

Partner Effects on a Woman's Intention to Conceive: 'Not with This Partner'

Current definitions of pregnancy intention that are useful at aggregate levels are weak at the individual level. This is especially true in social contexts where childbearing and pregnancy often occur within casual or transient relationships. Extensive data on lifetime partnerships and sexual behaviors, including pregnancies and births, from 250 low-income women who had experienced a total of 839 pregnancies are used to explore correlates of intention to conceive, as well as the extent to which women attribute their intentions to a current partnership. Some 57% of reported pregnancies were unintended. Overall, 21% of the women had not wished to conceive at least one of their pregnancies with the partner who impregnated them; that proportion rose to 33% among women who had had only unintended pregnancies. Even among women who had had no unintended pregnancies, 18% had had at least one conception that they had not wanted with their partner at the time of conception. Women were less likely to say they had not wanted to conceive with a particular partner if they were living with that partner than if they were not. The likelihood of not having wanted a pregnancy with a given partner rose with the lifetime number of serious partners. Pregnancies that were not wanted with a particular partner were more than twice as likely to end in abortion as were those that were (33% vs. 14%). Among these women, the desire to avoid childbearing relates more to the couple involved in the conception than to abstract notions of completed family size. It would therefore be useful to include items pertaining to partner relationships in future studies of pregnancy intention.

Women's labor, fertility, and the introduction of modern technology in a rural Maya village.

In the mid 1970s, the introduction of modern technology into a Maya subsistence agricultural village markedly increased the efficiency with which maize could be ground and water collected. This change in labor efficiency introduced a possible savings in the overall time that women allocate to work and, importantly, to energetic work. This article documents the response of female fertility to the introduction of laborsaving technology. Using two proximate determinants of female fertility, we look at the association between the advent of modern technology and changes in the age at which women give birth to their first child and the length of mothers' birth intervals. Analyses show that since the introduction of laborsaving technology, mothers have their first child at a younger age. Changes in birth intervals are less conclusive. Although completed family size is not known because many of the women in the sample are still in their childbearing years, women who initiate reproduction at a younger age can potentially have longer reproductive careers and larger families. Examining the relationship between female fertility and modern technology has important implications for the changes in demographics and economics now going on in many developing communities.

Urban Labor Markets, In-Migration, and Demographic Growth: Bremen, 1815-1914

In this study of the port city of Bremen during the nineteenth century, particular emphasis is placed on the impact of changing labor-market conditions on the structure of in-migration and the relative contribution of in-migrants to urban demographic growth. Until the 1880s, the persistence of pre-industrial employment structures limited the opportunities for permanent settlement. Family formation was delayed, and completed family size was smaller than in the case of the native born. Age- and disease-specific mortality data confirm that many in-migrants remained marginal elements within urban society. Only following the onset of industrialization in the late nineteenth century was there a significant improvement in in-migrant mortality. By 1905, the life expectancy of in-migrant men was generally higher than that of their native-born counterparts; the benefits for in-migrant women were even more substantial.

Inbreeding Effects on Fertility in Humans: Evidence for Reproductive Compensation

The effects of inbreeding on prereproductive mortality have been demonstrated in many natural populations, including humans. However, little is known about the effects in inbred individuals who survive to adulthood. We have investigated the effects of inbreeding on fertility among inbred adult Hutterites and demonstrate significantly reduced fecundity among the most inbred Hutterite women, as evidenced by longer interbirth intervals (P=.024) and longer intervals to a recognized pregnancy (P=.010) but not by increased rates of fetal loss (P>.50). These data suggest the presence of recessive alleles that adversely affect fecundity among the population. In contrast, completed family sizes do not differ among the more and the less-inbred Hutterite women who were born after 1920, suggesting that reproductive compensation is occurring among the more-inbred and less-fecund women. This recent reproductive strategy would facilitate the maintenance of recessive alleles and contribute to an overall decline in fertility in the population.

Effects of the status of women on the first-birth interval in Indian urban society.

The status of women, which is relative and multidimensional, has an important bearing on any long-term reduction in fertility. In Indian society, where cohabitation and childbearing are socially sanctioned only after marriage, the length of the first-birth interval affects the completed family size by influencing the spacing and childbearing pattern of a family. This study examines the influence of certain aspects of the status of married women--education, employment, role in family decision making, and age at marriage--along with three socioeconomic variables--per capita income of the family, social position of the household, and the caste system--on the duration of the first-birth interval in an urban Hindu society of the north-east Indian state of Assam. The data were analysed by applying life table and hazard regression techniques. The results indicate that a female's age at marriage, education, current age, role in decision making, and the per capita income of the household are the main covariates that strongly influence the length of the first-birth interval of Hindu females of urban Assam. Of all the covariates studied, a female's education appears to be a key mediating factor, through its influence on her probability of employment outside the home and thereby an earned income and on her role in family decision making. Unlike other Indian communities, the effect of the caste system does not have a significant effect on first-birth timing in this urban Hindu society.

The coevolution of human fertility and wealth inheritance strategies.

Life history theory concerns the scheduling of births and the level of parental investment in each offspring. In most human societies the inheritance of wealth is an important part of parental investment. Patterns of wealth inheritance and other reproductive decisions, such as family size, would be expected to influence each other. Here I present an adaptive model of human reproductive decision-making, using a state-dependent dynamic model. Two decisions made by parents are considered: when to have another baby, and thus the pattern of reproduction through life; and how to allocate resources between children at the end of the parents' life. Optimal decision rules are those that maximize the number of grandchildren. Decisions are assumed to depend on the state of the parent, which is described at any time by two variables: number of living sons, and wealth. The dynamics of the model are based on a traditional African pastoralist system, but it is general enough to approximate to any means of subsistence where an increase in the amount of wealth owned increases the capacity for future production of resources. The model is used to show that, in the unpredictable environment of a traditional pastoralist society, high fertility and a biasing of wealth inheritance to a small number of children are frequently optimal. Most such societies are now undergoing a transition to lower fertility, known as the demographic transition. The effects on fertility and wealth inheritance strategies of reducing mortality risks, reducing the unpredictability of the environment and increasing the costs of raising children are explored. Reducing mortality has little effect on completed family sizes of living children or on the wealth they inherit. Increasing the costs of raising children decreases optimal fertility and increases the inheritance left to each child at each level of wealth, and has the potential to reduce fertility to very low levels. The results offer an explanation for why wealthy families are frequently also those with the smallest number of children in heterogeneous, post-transition societies.

Trends in American family size diversity

How diverse is American society and are Americans becoming more or less diverse? Contemporary discussions claim high and increasing diversity, but analyze few actual trends. This paper examines completed family size diversity from 1940 to 2000 by race and across US states. For all groups, regions and the USA as a whole, family size diversity decreased significantly, produced by a combination of fewer small and large families and a general decline in regionally-based differences. Both within and across states the diversity declined in two stages, but regional clusters of states followed different paths. A cluster of Southern Mountain states showed the greatest contrast. Between the 1940s and the early 1970s, a slight baby boom rise in diversity among homogeneous states, was counterbalanced by declining diversity in more diverse states. Black women in all states and white women in Mainstream and Other states showed similar trends during the baby boom years, while white women in the Southern Mountain states failed to show a baby boom increase in large families. For childbearing completed since 1975, regional patterns disappeared and both the range and level of diversity declined further. A national and essentially homogeneous culture of childbearing, initiated during the baby boom years and now facilitated by birth control and abortion, has settled in at below-replacement levels. While the possibility always exists that childbearing pattern might change, there is no current evidence to suggest movement away from this low and homogeneous fertility.

Chinese Lunar Birth Timing in Singapore: New Concerns for Child Quality amidst Multicultural Modernity

This study examines lunar births by season and birth order and lunar births among intermarried Chinese mothers and fathers in Singapore. Lunar birth timing increased during 1970-90 in Singapore as modernization increased. Modernization is not expected to weaken the influence of lunar birth timing in the future. Staggered births create problems for the educational system. The lunar birth pattern in Singapore included a baby boom during the Year of the Dragon and a baby bust during the Year of the Tiger. This study demonstrates the unambiguous influence of culture on childbearing. The timing of births corresponds to the traditional lunar zodiac calendar in 12-year intervals. The short shifts in birth timing have implications for completed family size and are not explained by socioeconomic factors. Lunar birth timing appears among Chinese in other Asian countries with the exception of China. Data are obtained from Singapores vital registration system for the period 1970-90. Births among all ethnic groups declined by 1975. However troughs appeared in the Tiger years of 1974 and 1986 for the Chinese. In 1974 declines appeared for all but first births which increased due to the increase in marriage during 1973-74. Increases in Dragon year births were weaker among women with five or more births. Findings from other countries indicate that birth declines during the Year of the Tiger were widespread among the literate social classes regardless of educational level. Seasonal patterns differed between the Dragon and Tiger years. Annual sex ratios at birth did not show gender selection in lunar timing. Findings indicate that intermarried Chinese were more likely to show lunar preferences in birth timing. The degree of lunar timing increased by 1986 but Chinese intermarried wives dominated preferences during the Year of the Tiger and husbands dominated during the Year of the Dragon.

Ideal-family-size and Sex-composition Preferences among Wives and Husbands in Nepal

This study tests the hypothesis that, in Nepal, measures of ideal family size mask an underlying preference for sons, making some people willing to have families larger than their ideal. Existing evidence suggests that men are likely to have stronger preferences for sons than are women. This research uses empirical evidence to examine the hypothesis that husbands are more willing than their wives to pursue the birth of sons at the cost of an increasingly large completed family size. A Multiple-response Fertility Preference Scale was developed to test these propositions among a sample of couples. The methodology was successful in demonstrating differential patterns of decisionmaking between husbands and wives that are otherwise obscured by more simplistic, single-response measures (for example, ideal family size). The results indicate that husbands are consistently more willing than their wives to pursue the birth of sons at the expense of larger family sizes, and that the birth of daughters is not pursued to a similar degree by wives or husbands.

Fertility, family size preferences and future fertility prospects of men in the western area of Sierra Leone.

This paper examines the current fertility of men and women in the Western area of Sierra Leone and the prospects for future fertility behaviour. Probably due to the effect of rapid economic decline in Sierra Leone since 1980, the desired family size has fallen. But indications are that the preferred completed family size is lower than the desired family size.

Infertility and forager demography.

A model of the effects of infectious sterility on reproductive histories of women was presented to criticize the recent treatment of comparative forager population statistics, in which Blurton Jones et al. suggest that Hadza fertility is higher than ]Kung fertility because the Hadza have more food and a lighter workload. Infectious infertility in the ]Kung is a better explanation of the difference. Mean length of the reproductive span is a better indicator of the presence of infectious infertility than the primary sterility rate. A Markov chain model of reproduction had 4 states: at risk, pregnant, lactating, and sterile. The probability that a woman becomes sterile before she has a birth is in fair agreement with Howell's suggestion that 10% of ]Kung women never had a live birth. This agreement suggests that there was little exposure to sterility before the onset of full fecundity in this population. It is likely that the sexual partners of young ]Kung women were age mates rather than older men who would be more likely to transmit infection. The ]Kung share their land in Botswana with the Herero, who suffered severe infertility before antibiotics became available in the 1960s. In older Herero cohorts, primary sterility was only 15%, while sterility at every parity above zero was 25%. The cumulative effect of infertility in the Herero was severe: completed family size in older cohorts was less than 3 and the mean age at last birth was 27. The Herero example shows that the overall effects of sterility on reproduction and the level of primary sterility are not simply related.