Infant deaths, fetal deaths and shared obituary causes: implications and a new analytical perspective on infant mortality

Infant mortality rate (IMR), or number of infant deaths per 1000 livebirths, varies widely across the US While fetal deaths are not included in this measure, reported infant deaths do include those delivered at previable gestations, or ≤20weeks gestation. Variation in reporting of these events may have a significant impact on IMR estimates. This retrospective analysis used US National Center for Health Statistics 2007-2013 data from 2391 US counties. Counties were categorised by US region, demographic characteristics, and state-level fetal death reporting requirements. County percentage of fetal deaths among all 17-20week fetal and infant deaths was evaluated using multivariable linear regression. County-level characteristics were then included in multivariable linear regression to determine the associated change in county IMR. County percentage of deaths at 17-20weeks reported as fetal ranged from 0% to 100% (mean 63.7%). Every 1 point increase in this percentage was associated with a 0.02 point decrease in county IMR (95% confidence interval (CI) 0.02, 0.03). When county IMRs were recalculated holding the percentage of fetal vs. infant deaths at 17-20weeks constant at 63.7%, results suggest that the predicted gap in county IMR between Northeast and Midwest regions would narrow by 0.45 points. Variable reporting of previable fetal and infant deaths may compromise the validity of county IMR comparisons. Improved consistency and accuracy of fetal and infant death reporting is warranted.

Background: Air pollution is linked to adverse pregnancy outcomes such as preterm births, but few studies evaluated its acute impact on fetal and infant mortality. We evaluated short-term impacts of warm-season ozone and cold-season fine particulate matter <2.5 microns (PM2.5) exposures on the risk of fetal death (>20 weeks) and infant mortality (live birth to one year). Methods: This time-stratified case-crossover analysis includes 1,880 singleton fetal deaths (2007-2011) and 3,229 singleton infant deaths (2007-2015) from the San Joaquin Valley (SJV), California. Daily ozone and PM2.5 were estimated by the SJV Air Pollution Control District and geospatially linked to maternal zip code at birth. Critical exposure windows of interest included the day of death (lag 0) up to 14 days before (lag 14). Conditional logistic regression models estimated the odds ratio (OR) and 95% confidence intervals (CI) for each 5 units increase in pollutant. Results: In warm season (May-October), a 5-ppb increase in ozone was associated with a 7% (95% CI: 2%-13%) increased risk of fetal death and 6% (95% CI: 2%-10%) increased risk of infant death within two weeks. The estimates were generally consistent from lag 0 to lag 14 for both mortality outcomes, with evidence of slightly stronger estimates for fetal death compared to infant death during certain lags. During lag 7, a 5-ppb increase in ozone was associated with a 9% increased risk in fetal death (95% CI: 5%-14%) and a 4% (95% CI: 1%-7%) increased risk in infant death. No associations were observed for cold-season PM2.5. Conclusions: Ozone exposure is positively associated with short-term risk of fetal and infant mortality in the warm season. Given the ubiquitous nature of air pollution, these associations merit further investigation. Meanwhile, efforts to minimize exposures among pregnant women may be warranted. Keywords: pollution, infant mortality, fetal death, stillbirth, pregnancy, mortality, ozone

Early pregnancy obesity (body mass index, BMI, ≥ 30 kg/m(2)) carries significant health implications. This cohort study investigates the association between early pregnancy BMI and the risk of fetal and infant death in pregnancies not affected by congenital anomalies or pre-gestational diabetes. Data on singleton pregnancies delivered during 2003-2005 at five hospitals were linked with data from three regional registers: the Northern Perinatal Mortality Survey, the Northern Diabetes in Pregnancy Survey and the Northern Congenital Abnormality Survey. Logistic regression models were used to determine the crude and adjusted odds ratios (aOR) of a spontaneous fetal death (≥ 20 weeks gestation) and infant death (aged up to 1 year), among underweight (BMI <18.5 kg/m(2)), overweight (BMI 25-29.9 kg/m(2)) and obese women compared with women of recommended BMI (18.5-24.9 kg/m(2)). Obese women were at significantly increased risks of both fetal death [aOR = 2.32 (95% confidence interval: 1.64-3.28), P< 0.001] and infant death [aOR = 1.97 (1.13-3.45), P= 0.02]. Continuous analyses revealed a V-shaped relationship between BMI and the risk of fetal and infant death, with a minimum risk at 23 kg/m(2), and significantly increased risk thereafter for both fetal death [aOR, per unit = 1.07 (1.05-1.10), P< 0.001] and infant death [aOR, per unit = 1.06 (1.02-1.10), P= 0.007]. No significant excess risks, however, were identified for either maternal underweight [fetal death: aOR = 0.98 (0.42-2.25), P= 0.96; infant death: aOR = 1.89 (0.73-4.88), P= 0.19] or maternal overweight [fetal death: aOR = 1.34 (0.94-1.89), P= 0.10; infant death: aOR = 1.35 (0.79-2.32), P= 0.27] as categories. Except for higher rates of pre-eclampsia among stillbirths, no specific cause of death could explain the increased odds of fetal and infant death among the obese. Early pregnancy obesity is significantly associated with fetal and infant death, independent of the known relationships with congenital anomalies and maternal pre-gestational diabetes.

BackgroundPre-gestational diabetes is associated with a range of adverse pregnancy outcomes, including an increased risk of major congenital anomalies. The impact on normally-formed offspring, however, is less well defined. This...

Although maternal cigarette smoking has been shown to reduce the birth weight of an infant, previous findings on the relation between smoking and fetal and infant mortality have been inconsistent. This study used the largest data base ever available (360,000 birth, 2,500 fetal death, and 3,800 infant death certificates for Missouri residents during 1979-1983) to assess the impact of smoking on fetal and infant mortality. Multiple logistic regression was used to estimate the joint effects of maternal smoking, age, parity, education, marital status, and race on total mortality (infant plus fetal deaths). Compared with nonsmoking women having their first birth, women who smoked less than one pack of cigarettes per day had a 25% greater risk of mortality, and those who smoked one or more packs per day had a 56% greater risk. Among women having their second or higher birth, smokers experienced 30% greater mortality than nonsmokers, but there was no difference by amount smoked. The prevalence of smoking in this population was 30%. It was estimated that if all pregnant women stopped smoking, the number of fetal and infant deaths would be reduced by approximately 10%. The higher rate of mortality among blacks compared with whites could not be attributed to differences in smoking or the other four maternal characteristics studied. In fact, the black-white difference was greater among low-risk women (e.g., married multiparas aged 20 and over with high education) than among high-risk women (e.g., unmarried teenagers with low education).

ObjectiveTo investigate the association between maternal obesity and the prevalence of fetal and infant death.DesignCohort study using prospectively collected data matched to a high-quality population-based registry data of fetal and...

Accurately measuring maternal mortality trends has been challenging due to changes in data collection. This work disambiguates trends from the effects of introducing the pregnancy checkbox on death certificates and also analyzes closely related fetal and infant mortality. To describe trends in maternal, fetal, and infant deaths since 2000, including the impact of the COVID-19 pandemic. A national, population-level, epidemiological, cross-sectional analysis during 2000 to 2023 was conducted as well as a staggered difference-in-differences analysis on the pregnancy checkbox, using the US Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research (WONDER) database on underlying causes of death in the US to identify maternal, infant, and fetal deaths. Study population was restricted to mothers aged 15 to 44 years for all definitions of maternal mortality. Staggered introduction of the pregnancy checkbox on death certificates across different states. Longitudinal study (2000-2023) reporting crude rates per 100 000 population for adjusted maternal mortality and per 1000 population for fetal and infant mortality at the national level and by US Census Bureau-designated main census regions, age groups, and race and ethnicity. Staggered difference-in-differences counterfactuals (1999-2023) on impact of pregnancy checkbox. The introduction of the pregnancy checkbox was associated with 6.78 (95% CI, 1.47-12.09) deaths per 100 000 live births increase in reported maternal mortality, 66% (95% CI, 14%-117%) of the total increase from 2000 to 2019, with a smaller impact on maternal mortality excluding cause unspecified (adjusted maternal death rates). Adjusted maternal death rates remained consistently between 6.75 (95% CI, 5.97-7.61) to 10.24 (95% CI, 9.22-11.34) per 100 000 live births from 2000 until 2021, when it peaked at 18.86 (95% CI, 17.48-20.32); the rate dropped to 10.23 (95% CI, 9.22-11.32) in 2022. The death rates of Native American or Alaska Native women increased the most during the COVID-19 period, almost tripling from 2011 to 2019 (10.70 per 100 000 live births; 95% CI, 7.64-14.57) to the 2020 to 2022 period (27.47 per 100 000 live births; 95% CI, 18.39-39.45). The death rates of non-Hispanic Black women were highest across time-approximately triple the rate of non-Hispanic White women in each time period. Infant death rates per 1000 live births dropped from 6.93 (95% CI, 6.85-7.01) in 2000 to 5.44 (95% CI, 5.36-5.51) in 2020, increasing slightly to 2018 levels in 2021 to 2023. Fetal death rates per 1000 live births decreased from 6.28 (95% CI, 6.16-6.31) in 2005 to 5.53 (95% CI, 5.45-5.60) in 2022. Using difference-in-differences analyses, results of this study reveal that the pregnancy checkbox explained much of the observed increase in maternal mortality before the COVID-19 pandemic. Nevertheless, results of this cross-sectional study suggest that, even adjusting for pregnancy checkbox effects, most groups saw increases from 2011 to 2019 to the 2020 to 2022 period, indicating that the COVID-19 pandemic led to worse outcomes. The findings demonstrate the relevance of public health emergencies to maternal health outcomes.

To systematize knowledge on the activities developed by the committees involved in the prevention of infant and fetal deaths. Integrated literature review conducted in November 2015 at PubMed, CINAHL, Scopus, LILACS, BDEnf and SciELO databases using keywords and descriptors of infant mortality, infant death, infant deaths, fetal death, fetal deaths, fetal mortality, neonatal mortality, professional committee, committee, committees, advisory committees. The 34 selected studies were organized and analyzed using Microsoft Excel®. International, national, regional, state and local committees analyze the deaths and conduct activities aimed to qualify maternal and childcare and feed the health information systems. The committees for the prevention of infant and fetal mortality collect, produce, analyze and disseminate information related to these deaths in order to reduce infant and fetal mortality rates.

Trends in fetal and infant deaths caused by congenital anomalies

Prior observational research has shown that infants born in states with more abortion restrictions are more likely to die during infancy. It is unclear how recent and more severe abortion bans in the US have impacted infant mortality. To examine whether Texas Senate Bill 8 (SB8), which banned abortions after embryonic cardiac activity and did not allow exemptions for congenital anomalies, is associated with infant mortality in the state of Texas. This population-based cohort study of all recorded infant deaths from the state of Texas and 28 comparison states used a comparative interrupted time series analysis with an augmented synthetic control approach and national birth certificate data from January 1, 2018, to December 31, 2022, to estimate the difference between the number of observed and expected infant and neonatal deaths and death rates among monthly cohorts exposed to Texas' SB8. Deaths in March 2022 were treated as the first cohort exposed to the Texas' SB8 abortion policy because these infants (if born full term) were approximately 10 to 14 weeks' gestation when SB8 went into effect on September 1, 2021. The exposure period was thus March through December 2022. Our outcomes were monthly counts and rates of infant (aged <1 year) and neonatal (aged <28 days) deaths in the exposure period in Texas. In secondary analyses, annual changes in cause-specific infant deaths between 2021 and 2022 in Texas and the rest of the US were examined. Between 2018 and 2022, there were 102 391 infant deaths in the US, with 10 351 of these deaths occurring in the state of Texas. Between 2021 and 2022, infant deaths in Texas increased from 1985 to 2240, or 255 additional deaths. This corresponds to a 12.9% increase, whereas the rest of the US experienced a comparatively lower 1.8% increase. On the basis of the counterfactual analysis that used data from Texas and eligible comparison states, an excess of 216 infant deaths (95% CI, -122 to 554) was observed from March to December 2022, or a 12.7% increase above expectation. At the monthly level, significantly greater-than-expected counts were observed for 4 months between March and December 2022: April, July, September, and October. An analysis of neonatal deaths found somewhat similar patterns, with significantly greater-than-expected neonatal deaths in April and October 2022. Descriptive statistics by cause of death showed that infant deaths attributable to congenital anomalies in 2022 increased more for Texas (22.9% increase) but not the rest of the US (3.1% decrease). This study found that Texas' 2021 ban on abortion in early pregnancy was associated with unexpected increases in infant and neonatal deaths in Texas between 2021 and 2022. Congenital anomalies, which are the leading cause of infant death, also increased in Texas but not the rest of the US. Although replication and further analyses are needed to understand the mechanisms behind these findings, the results suggest that restrictive abortion policies may have important unintended consequences in terms of trauma to families and medical cost as a result of increases in infant mortality. These findings are particularly relevant given the recent Dobbs v Jackson Women's Health Organization US Supreme Court decision and subsequent rollbacks of reproductive rights in many US states.

Although nearly all countries have noted a marked drop in infant mortality in recent decades, there are still large disparities between countries, particularly between developed and developing nations but also among industrialized countries. Nations employ different gestational age and/or birth-weight cutoff points for reporting fetal deaths and live births. Interpretations of signs of life, which classify deaths as fetal or infant, may vary widely despite attempts at standardization by the World Health Organization. There also may be differences in registering tiny preterm infants as live births or fetal deaths. The authors analyzed data on six national groups from the Internal Collaborative Effort on Perinatal and Infant Mortality (whites and blacks in the United States, Israeli Jews and non-Jews, Norwegians, and Swedes) for the years 1987 and 1988. In particular, two major potential artifacts that might help explain intercountry differences in infant mortality were examined: classification as fetal or infant death (especially at very low birth weights) and underregistration of borderline-viable infants as either fetal deaths or live births. Crude infant mortality rates (infant deaths per 1000 live births) were lowest in Sweden, where they were 25% below those for Norway, US whites, and Israeli Jews. Rates were twice as high for US blacks and Israeli non-Jews. Mortality risk was reduced in both US groups and Israeli non-Jews after adjusting for maternal age, parity, and multiple births. Excluding Sweden (because of insufficient data), stillbirths of 20 weeks' or more gestation as a proportion of all perinatal deaths were highest in Norway and lowest in US blacks. Differences were most marked when birth weight was less than 500 g. Live births of less than 500 g varied more than 50-fold between Sweden and both Israeli groups at the low end and US blacks at the high end. US whites had a 15-fold higher proportion of live births less than 500 g than did Swedes. Rates for live births at 500 to 749 g varied 7-fold among the various groups, but again were lowest in Sweden and highest in US blacks. Live births less than 750 g were much likelier to be registered in the United States than in the other countries, and this was not simply a reflection of differential classification of live births and stillbirths. Excluding births less than 750 g, the relative risk of infant mortality was somewhat reduced for Swedes, Israeli Jews and non-Jews, and US whites, and it was markedly reduced for US blacks. Relative risk figures for both Israeli groups and both US groups (especially US blacks) declined after adjusting for maternal age, parity, and multiple gestation. These findings confirm the existence of marked differences in registering infants near borderline viability as well as differences in classifying fetal versus infant deaths. Information updating these figures, now more than a decade old, is needed. In addition, more in-depth studies are required to ascertain the reasons for these differences, whether cultural, religious, or economic.

Research in brief

Fetal and infant death and serious neonatal morbidty are important adverse outcomes in perinatology. The definitions of these terms, the timing of fetal death (e.g., early fetal death and late fetal death; antepartum and intrapartum), the timing of infant death (early neonatal, late neonatal and post-neonatal) and the conventions for estimating rates (period and birth cohort types of infant mortality) are critical for making appropriate comparisons of temporal changes and regional differences in mortality and morbidity. These issues are highlighted using contemporary information on international infant mortality rates. Other issues discussed in the chapter include the Millennium Development Goals, causes of death, the principal types of serious neonatal morbidity, cerebral palsy, recent interventions that have affected infant morbidity and mortality rates. Specific conceptual and semantic issues that arise in the perinatal epidemiologic literature are also discussed.

BackgroundUnited States state-level income inequality is positively associated with infant mortality in ecological studies. We exploit spatiotemporal variations in a large dataset containing individual-level data to conduct a cohort study and to investigate whether current income inequality and increases in income inequality are associated with infant and neonatal mortality risk over the period of the 2007–2010 Great Recession in the United States.MethodsWe used data on 16,145,716 infants and their mothers from the 2007–2010 United States Statistics Linked Infant Birth and Death Records. Multilevel logistic regression was used to determine whether 1) US state-level income inequality, as measured by Z-transformed Gini coefficients in the year of birth and 2) change in Gini coefficient between 1990 and year of birth (2007–2010), predicted infant or neonatal mortality. Our analyses adjusted for both individual and state-level covariates.ResultsFrom 2007 to 2010 there were 98,002 infant deaths: an infant mortality rate of 6.07 infant deaths per 1000 live births. When controlling for state and individual level characteristics, there was no significant relationship between Gini Z-score and infant mortality risk. However, the observed increase in the Gini Z-score was associated with a small but significant increase likelihood of infant mortality (AOR = 1.03 to 1.06 from 2007 to 2010). Similar findings were observed when the neonatal mortality was the outcome (AOR = 1.05 to 1.13 from 2007 to 2010).ConclusionsInfants born in states with greater changes in income inequality between 1990 and 2007 to 2010 experienced a greater likelihood of infant and neonatal mortality.

Prenatal diagnosis and termination of affected pregnancies can prevent infant deaths due to congenital anomalies, but an effect at the population level has not been shown. To examine the impact of recent changes in congenital anomaly-related fetal and infant deaths on overall population-based infant mortality. Birth cohort-based study of all live births, stillbirths, and infant deaths in Canada (excluding Ontario) for 1991-1998. Cause-specific infant mortality rates and gestational age-specific fetal death rates. The birth cohort-based infant mortality rate fluctuated between 6.4 and 6.1 per 1000 live births between 1991 and 1995, then dropped to 5.4 per 1000 in 1996 and 5.5 per 1000 in 1997. The rate of infant death from congenital anomalies was stable between 1991 and 1995 but declined by 21% (95% confidence interval, 19%-32%) from 1.86 per 1000 in 1995 to 1.47 per 1000 in 1996 and 1997. Fetal deaths due to pregnancy termination at 20 to 23 weeks' gestation increased dramatically in 1994, while fetal deaths due to congenital anomalies at 20 to 21 weeks increased in 1995 and subsequently. Provinces/territories with high rates of fetal death due to pregnancy termination/congenital anomalies at 20 to 23 weeks had fewer infant deaths due to congenital anomalies. A large decrease in infant deaths due to congenital anomalies was associated with the most recent decline in infant mortality in Canada, suggesting that increases in prenatal diagnosis and pregnancy termination for congenital anomalies are related to decreases in overall infant mortality at the population level.