High foetal mortality and birth intervals

Abstract Studies of birth intervals have generally separated the process into: (1) the period of infertility following a pregnancy termination; (2) the length ofthe interval from the end of the infertile period to the next conception (which reflects the probability of conception), and (3) the average duration of pregnancy for both live births and foetal deaths.(1) Empirically derived intervals between successive live births average from 19 to 30 lunar months(2) (Table 1), depending upon the population studied and the birth order.(3) Estimates of conception rates using birth intervals data require some estimate of the extent to which foetal wastage increases the birth interval.     

Determinants of birth intervals and their means

Abstract 1. The duration of post-partum infecundity; 2. Fecundability; 3. Duration of pregnancy.     

Population dynamics based on birth intervals and parity progression

Abstract The Chinese population policy of 'later-longer-fewer' suggests a formulation of population dynamics in terms of birth intervals and parity progression. This leads to population projections based on birth interval distributions and parity progression ratios and to an alternative to Lotka's stable population theory in which age is replaced by parity and interval since last birth. A numerical comparison with Lotka's model indicates similarities and differences between the two approaches: The formulation suggests an approach to the analysis of birth interval and parity progression statistics that effectively solves censoring and selection problems.     

Infant mortality in the Marshall Islands

Levy and Booth present previously unpublished infant mortality rates for the Marshall Islands. They use an indirect method to estimate infant mortality from the 1973 and 1980 censuses, then apply indirect and direct methods of estimation to data from the Marshall Islands Women's Health Survey of 1985. Comparing the results with estimates of infant mortality obtained from vital registration data enables them to estimate the extent of underregistration of infant deaths. The authors conclude that 1973 census appears to be the most valid information source. Direct estimates from the Women's Health Survey data suggest that infant mortality has increased since 1970-1974, whereas the indirect estimates indicate a decreasing trend in infant mortality rates, converging with the direct estimates in more recent years. In view of increased efforts to improve maternal and child health in the mid-1970s, the decreasing trend is plausible. It is impossible to estimate accurately infant mortality in the Marshall Islands during 1980-1984 from the available data. Estimates based on registration data for 1975-1979 are at least 40% too low. The authors speculate that the estimate of 33 deaths per 1000 live births obtained from registration data for 1984 is 40-50% too low. In round figures, a value of 60 deaths per 1000 may be taken as the final estimate for 1980-1984.     

Seasonal migration and seasonal variation in fecundabillty: Effects on birth rates and birth intervals

Seasonal patterns in conception rates have been documented in several recent studies. In this paper, a mathematical model of the reproductive process is developed through which the impact of such variation in conception rates is assessed. It is found that the effect on fertility can be quite substantial, but that the birth rate when seasonal variation is occurring is approximated well by the birth rate calculated when conception rates are constant at their mean. These results indicate that further documentation of seasonality in conception rates and exploration of the causes of these patterns and their change is an important area for demographic research.     

Open and closed birth intervals for once-married spouse-present white women

Using the 1970 1/1,000 Public Use Sample of the U.S. population, the relationships of the closed and open birth intervals with parity and mother's age, with parity and marital duration, and with children ever born/marital duration and mother's age are analyzed. These findings both replicate and expand on Srinivasan's earlier research on the open interval. The open interval is more sensitive as an index of marital fertility when marital duration and parity are controlled than when mother's age and parity are controlled.     

Infant mortality trends in rural East Pakistan

Infant mortality trends in a rural area of East Pakistan are analyzed utilizing the Bogue pregnancy history technique. The findings indicate that infant mortality has declined slightly over 20 percent between 1958 and 1967. The existence of development programs in women’s education and family planning since 1961 are proposed as possible reasons for this finding. A convergence in infant mortality rates to mothers in the age range 15–39 years was found in the final year under analysis, while the standard U shaped pattern of infant mortality with age structure was exhibited in the previous years. One possible explanation for the convergence is that the development programs are reaching women within this age range more equally than in the past. An alternative explanation relating to the problems of recall of mortality events was discussed.     

Infant mortality decline in Chile: A replication

This replication of a previous analysis of the effect of sociological variables on infant mortality rates in Chile refines the earlier work by using the more numerous communes for comparisons, by presenting the basic data in the form of a path analysis, and by expanding the theory to include “health practices,” customs, such as avoiding teenage pregnancies, that are community-backed and maintained. This type of practice is then integrated into the “institutionalized problem-solving capacity” framework that guides the analysis. Urabnization and voting, the two indicators of institutionalized problem-solving capacity, predict reduced infant morality, as before. Teen pregnancies is a positive predictor, as expected, but the number of children already born does not predict. These results are net of two indicators of health technology-whether or not a physician was in attendance, and the number of clinics. Mother's education also predicted low infant morality, and the theory is applied to this well-known predictor to interpret its effect. In addition, the anomalous role of mother's education in the dominant biomedical explanation is highlighted.     

Interpreting demographic effects in duration analyses of first birth intervals

Estimated demographic effects in proportional hazard models of first birth intervals could reflect time-invariant differences in the risk of a birth, or differences in the timing of a shift in the risk, or both. This paper attempts to distinguish between these possibilities. The procedure is to estimate a more general model than the proportional hazard specification, in which the evolution of the risk of a birth can differ with demographic characteristics. The proportional hazard specification is nested within this more general model. Consequently, the consistency of the data with the risk or the timing interpretation of demographic effects can be tested. The data studied do not lead to a rejection of the proportional hazard specification.Department of Economics, University of Pennsylvania. The initial stage of this research was supported by a National Science Foundation Graduate Fellowship. I have benefited from insightful comments from David Bloom, Andrew Foster, Zvi Griliches, V. Joseph Hotz, Duncan Thomas, anonymous referees, and participants in seminars at Harvard University and the University of Pennsylvania, and in the Economic Demography sessions of the 1988 Population Association of America annual meetings. Any remaining errors are my own.     

Infant mortality and socioeconomic development: Evidence from Malaysian household data

Household data from Malaysia are used to assess the roles of a number of mortality correlates in explaining the inverse relationship between the infant mortality rate (IMR) and socioeconomic development. Increases in mothers' education and improvements in water and sanitation are the most important household-level changes that accompany regional and temporal development and contribute to the inverse relationship between the IMR and development. One concomitant of development--reduced reduced breastfeeding--has kept the relationship from being even stronger. Continued prevalence of extended breastfeeding in the poorer states of Peninsular Malaysia and a narrowing of educational and sanitation differentials helped close the IMR gap between the richer and the poorer states.     

Modelling period fertility: Schooling and intervals following a birth in Eastern Africa

We describe a regression-based approach to the modelling of age-, order-, and duration-specific period fertility, using retrospective survey data. The approach produces results that are free of selection biases and can be used to study differential fertility. It is applied to Demographic and Health Survey data for Ethiopia, Kenya, Tanzania, and Zimbabwe to investigate differential trends in fertility by education. Parity progression fell and the intervals following each birth lengthened between the 1970s and 2000s in all four countries. Fertility fell most among women with secondary education. In contrast to other world regions, postponement of successive births for extended periods accounted for much of the initial drop in fertility in these African countries. However, family size limitation by women with secondary education in Ethiopia and Kenya and longer birth spacing in Zimbabwe also played significant roles. Thus, birth control is being adopted in Eastern Africa in response to diverse changes in fertility preferences.     

Siblings’ neonatal mortality risks and birth spacing in Bangladesh

This paper studies the familial association of neonatal mortality in Matlab, Bangladesh and its relationship to birth-spacing effects on mortality. Findings show that familial association is strongest for siblings of adjacent birth orders. Moreover, birth-spacing effects on neonatal mortality are stronger when the preceding child has survived the neonatal period than when it has died. Transitional (Markov), random-effects, and marginal models for correlated data are introduced, and are contrasted in interpretation and technique. Familial association of neonatal mortality can be approximated well by a first-order Markov model using generalized estimating equations (GEE) to allow for higher-order correlation.     

Compromised birth outcomes and infant mortality among racial and ethnic groups

Demography - Research based on hospital records demonstrates that many births classified as normal according to conventional demographic measurement are intrauterine growth-retarded (IUGR) when...     

Findings and implications of a correlation analysis of the closed and the open birth intervals

A correlation analysis of data on four fertility variables viz. closed birth interval, open birth interval, age and parity, collected in a survey of about 2,000 married women in the reproductive ages in rural India, is carried out in order to study the interrelationships among these variables. Two hypotheses are formulated governing the relationship of the closed and open birth intervals with the fecundability distribution of fertile women, and Parity Progression Ratios which are largely influenced by the proportion of women becoming sterile after each parity. The data lend support to the hypothesis that while the closed intervals are influenced mainly by the distribution of fecundability of women of non-zero fecundability, the open birth intervals are influenced mainly by Parity Progression Ratios or the proportion of women becoming secondarily sterile after each parity. The analysis suggests that we can use the mean open intervals of women classified by parity as indices of fertility, and such an index is comparable to the index of average age of women of given parity. In areas where it is difficult to ascertain the correct age of women this might be of practical value.     

Childhood mortality,family size and birth order in pre-industrial Europe

Demography - Based on parish registers, demographic histories of Crulai (France), Tourouvre-au-Perche (France), and Geneva (Switzerland) established the childhood mortality experienced by complete...     

Infant and child mortality in India: trends in inequalities across economic groups

This paper examines the trends in economic inequalities with respect to infant and child mortality in India using three rounds of the Indian National Family Health Survey conducted in 1992–1993, 1998–1999, and 2005–2006. The paper uses concentration index, and pooled discrete-time survival regression model to examine the aforementioned trends and regional patterns. The findings suggest a decreasing trend in economic inequality in infant mortality but an upward trend in economic inequality in child mortality in India. Economic inequalities in infant mortality have narrowed in the southern region, whereas they have widened in the western region and risen in the northern region. However, mixed trends in concentration indices were found in the different regions of India in the case of child mortality.     

Adolescent social isolation and premature mortality in a Swedish birth cohort

Research shows consistently that social ties are important for longevity, and they may be particularly important during adolescence. An absence of social ties, or social isolation, during adolescence may adversely affect long-term health and wellbeing. While prior research has examined associations between isolation from friends and long-term health, and having no siblings and mortality, no study (of which we are aware) considers jointly both the role of having no friends and no siblings, nor more generally with whom adolescents spend time, and the risk of premature mortality. This paper extends the literature by drawing on data from the Stockholm Birth Cohort Study to examine the association between different types of social isolation during adolescence (i.e., an absence of friends, siblings, and time with other adolescents) and the risk of premature mortality by midlife. Results suggest that having no siblings, being unliked at school, and spending (mostly) no time with other adolescents, increases the risk of premature mortality. The association between being unliked and premature mortality was attenuated by demographic and adolescent characteristics. Consistent with our expectations, net of a robust set of covariates, adolescents who had no siblings and mostly spent no time with other adolescents (i.e., isolates) were the group most vulnerable to premature mortality by midlife. However, this was only true for females.

     

Starting age and subsequent birth intervals in cohabitational unions in current danish cohorts, 1975

This paper presents some main results of an investigation by life table methods of birth interval data in cohabitational unions (marriages as well as consensual unions) in current Danish cohorts. Our results confirm previous findings that an early age at the start of recorded exposure to childbearing risk is indicative of a rapid pace and high level of subsequent fertility. The analysis modifies previous results and adds several new details regarding cohort trends and the effect of parity at the start of reported cohabitation. For each parity within a period of cohabitation, fertility differentials by reported starting age seem to have diminished from our older cohorts (of age up to 49 years in 1975) to our younger ones (of age less than 30 years in 1975). There are indications of a dramatic change in childbearing behaviour following the arrival of novel attitudes to non-marital cohabitation and childbearing in Denmark about 1967.