Comment on “compromised birth outcomes and infant mortality among racial and ethnic groups”

Frisbie, Forbes, and Pullum (1996) show that it is meaningful to account for low birth weight, preterm delivery, and intrauterine growth-retardation when analyzing differences in compromised birth outcomes and infant mortality among racial and ethnic groups. I compare their findings for the 1987 U.S. birth cohort with findings for the 1988 U.S. birth cohort, using linked birth and infant death vital statistics from the National Center for Health Statistics. I focus on their calculation of fetal growth curves, which are highly at odds with the curves commonly used in the obstetric and pediatric literature. I compare birth outcome distributions and infant death probabilities using Frisbie et al. 's method and other standards. I conclude that Frisbie et al. 's method is not suited for the study of intrauterine growth-retardation at the population level because of the major flaws in gestational age measurement that exist in the type of data they use. An appropriate alternative is to apply a standard of normal intrauterine growth derived from antenatal estimation of fetal weight-for-gestational-age to the vital statistics data.     

Revising Infant Mortality Rates for the Early Twentieth Century United States

Accurate vital statistics are required to understand the evolution of racial disparities in infant health and the causes of rapid secular decline in infant mortality during the early twentieth century. Unfortunately, U.S. infant mortality rates prior to 1950 suffer from an upward bias stemming from a severe underregistration of births. At one extreme, African American births in southern states went unregistered at the rate of 15 % to 25 %. In this study, we construct improved estimates of births and infant mortality in the United States for 1915–1940 using recently released complete count decennial census microdata combined with the counts of infant deaths from published sources. We check the veracity of our estimates with a major birth registration study completed in conjunction with the 1940 decennial census and find that the largest adjustments occur in states with less-complete birth registration systems. An additional advantage of our census-based estimation method is the extension backward of the birth and infant mortality series for years prior to published estimates of registered births, enabling previously impossible comparisons and estimations. Finally, we show that underregistration can bias effect estimates even in a panel setting with specifications that include location fixed effects and place-specific linear time trends.     

Maternal Education, Birth Weight, and Infant Mortality in the United States

This research determines whether the observed decline in infant mortality with socioeconomic level, operationalized as maternal education (dichotomized as college or more, versus high school or less), is due to its “indirect” effect (operating through birth weight) and/or to its “direct” effect (independent of birth weight). The data used are the 2001 U.S. national African American, Mexican American, and European American birth cohorts by sex. The analysis explores the birth outcomes of infants undergoing normal and compromised fetal development separately by using covariate density defined mixture of logistic regressions (CDDmlr). Among normal births, mean birth weight increases significantly (by 27–108 g) with higher maternal education. Mortality declines significantly (by a factor of 0.40–0.96) through the direct effect of education. The indirect effect of education among normal births is small but significant in three cohorts. Furthermore, the indirect effect of maternal education tends to increase mortality despite improved birth weight. Among compromised births, education has small and inconsistent effects on birth weight and infant mortality. Overall, our results are consistent with the view that the decrease in infant death by socioeconomic level is not mediated by improved birth weight. Interventions targeting birth weight may not result in lower infant mortality.     

The impact of induced abortion on black and white birth outcomes in the United States

This paper examines the impact of induced abortion on birth outcomes by treating abortion as an endogenous input into the production of infant health. To gauge the direct and indirect effects of abortion, three measures of infant health are considered simultaneously: the neonatal mortality rate, the percentage of low-weight births, and the percentage of preterm births. All three are race specific and all pertain to large counties in the United States in 1977. The results suggest that by preventing unwanted births, abortion enhances the survivability of newborns of a given birth weight and improves the distribution of births among high-risk groups.     

Demographic models of birth outcomes and infant mortality: An alternative measurement approach

Most demographic studies use 2,500 grams of birth weight and 37 weeks of gestation as cutpoints for evaluating the effects of adverse birth outcomes on infant mortality. We propose an alternative strategy, which relies on continuous measures of birth outcomes, identifies an optimal combination of birth weight and gestational age for infant survival, and estimates the effects of adverse birth outcomes in terms of their departure from this "optimal point." We illustrate the advantages of this approach by estimating a logistic model using data from the 1989-1991 NCHS linked birth/infant death files. Finally, we discuss future applications and methodological issues to be resolved in subsequent research.     

The effect of natural disaster on fertility,birth spacing,and child sex ratio: evidence from a major earthquake in India

Natural disasters can lead to significant changes in health, economic, and demographic outcomes. However, the demographic effects of earthquakes have been studied only to a limited degree. This paper examines the effect of the 2001 Gujarat earthquake on reproductive outcomes. This earthquake killed more than 20,000 people; injured 167,000; and caused massive losses to property and civic assets. Using data from two large-scale District-Level Household Surveys (2002–2004 and 2007–2008), we employ difference-in-difference and fixed-effect regression models to compare the outcomes across earthquake-affected districts and their neighboring districts during 5 years before and after the earthquake. We find that the earthquake led to significant rises in childbirth rates. It also reduced birth spacing among uneducated, tribal, and Muslim women, and the incidence of male births among rural women. We find considerable variation in the demographic effects of the earthquake across location, household socioeconomic status, and parental age and education.     

The effects of pregnancy spacing on infant and child mortality in Matlab, Bangladesh: how they vary by the type of pregnancy outcome that began the interval

Using high-quality longitudinal data on 125,720 singleton live births in Matlab, Bangladesh, we assessed the effects of duration of intervals between pregnancy outcomes on infant and child mortality and how these effects vary over subperiods of infancy and childhood and by the type of outcome that began the interval. Controlling for other correlates of infant and child mortality, we find that shorter intervals are associated with higher mortality. Interval effects are greater if the interval began with a live birth than with another pregnancy outcome. In the first week of the child's life, the effects of short intervals are greater if the sibling born at the beginning of the interval died; after the first month, the effects are greater if that sibling was still alive. Many relationships found are consistent with the maternal depletion hypothesis, and some with sibling competition. Some appear to be due to correlated risks among births to the same mother.     

The effects of maternal smoking on infant health

Maternal smoking has serious consequences for the developing fetus and infant, including a higher probability that the infant will be born prematurely and at low birth weight, will require admission to neonatal intensive care, and die during infancy. Data from Alabama birth certificates for births occurring between 1988 and 1991 were analyzed using log linear methods to calculate relative risks of adverse pregnancy outcomes and infant death. Smoking by mothers during pregnancy is associated with an elevated risk of infant death, low birth weight, and prematurity, controlling for mother's educational attainment, age, marital status, race, and trimester prenatal care was initiated. Smoking was also associated with a higher rate of admission to neonatal intensive care and to deaths from SIDS and respiratory causes. Reducing maternal smoking can contribute to a reduction of premature and low weight births and infant deaths. Because of the difficulty of stopping smoking, efforts need to be directed at preventing younger women from beginning to smoke.An earlier version of this paper was presented at the Southern Demographic Association annual meeting in New Orleans in October 1993.     

Family Benefits and Fertility: An Econometric Analysis

A population's growth potential is significantly underestimated by conventional calculations of population momentum which assume an immediate drop to replacement level fertility. Here we assume that the growth rate of births linearly declines to zero over a specified time interval, and find simple and intuitively meaningful expressions for the size of the ultimate birth cohort and the resultant population momentum. In particular, we find that the increase in the number of births over the transition is equal to growth at the initial rate for half the time needed to attain a constant birth level. Thus our formula readily calculates the growth potential of a population under a gradual approach to stationarity without the need for a numerical projection. Calculations for actual and hypothetical populations are presented to show the demographic impact of such gradual approaches to zero growth.     

Racial differences in infant mortality by cause of death: The impact of birth weight and maternal age

This research examines racial disparities in infant mortality, overall and separately according to cause of death. Using linked birth and death records for the 1975 cohort of live births in Florida, racial differences are initially described and then explained statistically as a product of the distribution of births by birth weight and maternal age. The impact of birth weight is more pronounced than is the effect of maternal age. The analysis suggests the potential utility of examining infant mortality separately by cause of death. Based on the findings, we argue for systematic research focused on factors affecting birth weight.     

Demographic Determinants of Infant and Early Child Mortality: A Comparative Analysis

In this paper we examine the relative importance of a number of demographic determinants of infant and early child mortality using information from 39 World Fertility Survey countries. We include sex of the child, age of the mother at the time of the birth, birth order, mother's educational level and a number of indicators of spacing of adjacent births among the correlates of chances of survival for children below the age of five years. Mortality of firstborn children and of those born to teenage mothers is shown to be higher than average; that of later children and those of older mothers was not much higher than average, once other factors are controlled. Effects of poor birth-spacing persist even after other factors have been controlled, and are similar where a sib was born during the two years preceding the birth of the child, regardless of the survival status of that sib; however, mortality was higher when that sib had died, due to increased familial risks of mortality. Rapid subsequent births also raise mortality for their earlier sibs. The findings are generally remarkably consistent in a wide range of countries and associated mortality conditions, although attention is drawn to a few interesting geographically clustered exceptions which deserve further investigation. The study leaves little room for doubt that poor child-spacing is clearly linked to decreased survival chances.     

The Untold Story of 50 Years of Adolescent Fertility in West Africa: A Cohort Perspective on the Quantum,Timing, and Spacing of Adolescent Childbearing

Although recent studies examine overall fertility trends in West Africa, few using advanced demographic techniques focus on adolescents. This study explores long‐term patterns of adolescent childbearing in 12 West African countries using 51 Demographic and Health Surveys covering birth cohorts that span 54 years (1940–1994). We employ classic demographic measures as well as disaggregation by early‐ (10–14 years old), middle‐ (15–17), and late adolescence (18–19). Cohort‐based estimates of total adolescent births, parity progression ratios, and rapid repeat birth probabilities reveal little change over time. Most women begin childbearing in adolescence, the progression to additional adolescent births remains common, and the incidence of rapid repeat births is high. In recent cohorts, women exit adolescence with an average of between 0.4 (Ghana) to 1.3 (Niger) births. Contrary to common assumptions, it is women commencing motherhood in early‐ and middle‐, not later adolescence, who account for most West African adolescent fertility.     

Population statistics] as of July 1, 2000

This Mahidol Population Gazette presents Thailand's population and demographic estimates as of July 1, 2000, using the standard techniques of demographic analysis. The paper provides estimates of Thailand's total population, population by sex, population in urban and rural areas, population by region, and by age group. In addition, figures of crude birth and death are listed per 1000 population, natural growth rate, and infant mortality rate per 1000 live births, male and females' life expectancy at birth and at age 60, total fertility rate, contraceptive prevalence rate. The number of the aged population in 2020 is also presented. Presented in a bar graph is a population pyramid for Thailand in the year 2000, illustrating male and females' age and year of birth.     

Estimates of vital rates for the Canadian Indians, 1960–1970

The present paper is an attempt to evaluate the registered data on Canadian Indians collected by the Department of Indian Affairs and Northern Development and to prepare vital rates for 1960–1970 using the adjusted data. A cursory examination of registered data for the purpose of developing various demographic indices and for making future estimates of population indicates certain anomalies that call for a careful appraisal of the data. The main problem is the inconsistency in the reporting of births, due largely to the late registration of births. One plausible reason for late registration may be the increased outward movement of Indians from their reserves. Indirect methods are used to adjust the number of births and infant deaths reported annually since 1960. On the basis of the adjusted data, vital rates for the Canadian Indians are calculated for the period 1960–1970. The crude death rate decreased from 10.9 in 1960 to 7.5 in 1970. The infant mortality rate registered a drastic decline, from 81.5 deaths per 1,000 births in 1960 to 34.9 in 1970. During this same time period the birth rate also declined, from 46.5 to 37.2.     

Nonreporting of births or nonreporting of pregnancies? Some evidence from four rural counties in North China

Coale and Banister argue that in China, elevated sex ratios in retrospective surveys are in part a function of collecting birth histories in a culture in which the definition of a birth may exclude mortality shortly after birth: an infant death in the West may be a stillbirth in east Asia. I present data from a recent sample survey featuring a retrospective pregnancy history. These data reveal that at least in the first pregnancy, from which the preponderance of sample births arise, there is no evidence of elevated female infant mortality or of high numbers of stillbirths, but that reported sex ratios are unusually high. The proportion of stillbirths grows for later pregnancies, but not enough to account for high sex ratios. Retrospective fertility data regarding recall over a recent interval are vexed less by a misunderstanding of what a live birth is than by a “misunderstanding” of what a (reportable) pregnancy is.     

Population statistics] as of July 1, 1998

This article presents estimates of relevant population numbers and vital rates in Thailand as of July 1, 1998. Utilizing the standard demographic techniques of analysis, the estimates provided are assured to be the most accurate demographic estimates possible. Total population was estimated at 61,143,000. Estimates by sex, locales, region, and by age group are included. In addition, the crude birth rate per 1000 population was estimated at 18.7; the crude death rate per 1000 population was 6.5. For the natural growth rate the estimate was at 1.2%, and the infant mortality rate was 25.0 per 1000 live births. In terms of life expectancy at birth, the estimate for males was 69.9 years, while for females it was 74.9 years. Additional years in life expectancy at age 60 were 20.3 years for males and 23.9 years for females. The total fertility rate per woman is 1.98, and contraceptive prevalence is 72.2%. The demographic data will be disseminated to Thai and international population researchers and planners.     

Fear of childbirth and depressive symptoms among postnatal women: A cross-sectional survey from Chhattisgarh,India

Background

Prevalence rates of Fear of Birth and postnatal depressive symptoms have not been explored in Chhattisgarh, India.

Race/ethnic differentials in heavy weight and cesarean births

Objectives: The general objectives of this research are tofurther our understanding of the distribution and incidence of heavy weight births and to examine differentials in the use of cesarean section as a response to macrosomia in models that are more broadly comparative by race/ethnicity than any that have heretofore been estimated. Methods: The data are drawn from the combined 1989–1991 NCHS Linked Birth/Infant Death Cohort Files,a data set of over 12 million live births and over 100,000 infant deaths that allows for highly reliable estimations for relatively small race/ethnic sub populations. Results: The results confirm that previously identified determinants of macrosomia such as maternal diabetes,maternal weight gain, parity and a previous heavy weight infant are highly predictive of a macrosomic birth, independent of race/ethnic effects. With respect to the management of heavy weight births, race/ethnic differentials exist in the odds of a cesarean delivery, theprocedure most often used to limit the risks of a macrosomic delivery.     

The Apparent Failure of Russia's Pronatalist Family Policies

Russia has a history of pronatalist policies dating back to the 1930s. Two sets of pronatalist measures were implemented during the past 40 years. The one designed in the early 1980s proved to be a clear failure. Instead of raising fertility, completed cohort fertility declined from 1.8 births per woman for the 1960 birth cohort to 1.6 for the 1968 cohort. The government of President Putin became concerned with the dire demographic conditions of high mortality and low fertility in Russia in the 1990s and early 2000s. A comprehensive set of pronatalist measures came into effect in January 2007. The period total fertility rate increased from 1.3 births per woman in 2006 to 1.6 in 2011, which the authorities view as an unqualified success. An unbiased demographic evaluation as well as analyses of Russian experts reveals that apparently the measures mainly caused a lowering of the age at birth and shortening of birth intervals. It appears that any real fertility increase is questionable, i.e. cohort fertility is not likely to increase appreciably. The recent pronatalist measures are likely to turn out to be a failure.     

Premature birth and the changing composition of newborn infectious disease mortality: Reconsidering “exogenous” mortality

Linked death and birth records from San Antonio, Texas reveal that infectious infant mortality is increasingly a function of premature birth and low birth weight. Between 1935 and 1944, 4% of infectious infant deaths had associated causes involving prematurity and related conditions; by 1980, 25% of infectious infant deaths involved prematurity and more than 40% of those infants weighed less than 2,500 grams. The shift in birth-weight composition results almost entirely from an increase in very low-weight births. Under conditions of advanced perinatal technology, infectious infant mortality should no longer be viewed as wholly exogenous. These findings further undermine the contemporary relevance of the exogenous-endogenous distinction.