Gestational Age-specific Neonatal Mortality Research Articles

Neonatal mortality in singleton pregnancies: a 20-year retrospective study from a tertiary perinatal unit in Hong Kong.

The global neonatal death (NND) rate has been declining in recent decades, but there are no comprehensive data concerning the characteristics of NNDs in Hong Kong. This study investigated the trends and aetiologies of NNDs among singleton pregnancies in Hong Kong. This study included all cases of NND from singleton pregnancies in a tertiary hospital in Hong Kong between 2000 and 2019. The rates, clinical characteristics, and aetiologies of NND were compared between the first (2000-2009) and the second (2010-2019) decades. The NND rate decreased from 1.66/1000 livebirths (97 cases) in the first decade to 1.32/1000 livebirths (87 cases) in the second decade. Congenital or genetic abnormalities (82 cases) caused 44.6% of all NNDs. There was a significant reduction from 0.82/1000 livebirths in the first decade to 0.52/1000 livebirths in the second decade (P=0.037). Other causes of NND were prematurity (69 cases; 37.5%), sepsis (16 cases; 8.7%), hypoxic-ischaemic encephalopathy (15 cases; 8.2%), and sudden infant death syndrome (2 cases; 1.1%). Gestational age-specific neonatal mortality for moderately preterm neonates (31-33 weeks of gestation) significantly decreased from 34.73/1000 in 2000-2009 to 8.63/1000 in 2010-2019 (P=0.001), but there were no significant changes in neonatal mortality for other gestations. The NND rate in Hong Kong is among the lowest worldwide. Neonatal deaths in our centre declined over the past two decades, mainly because of improvements in the prenatal diagnosis and treatment of congenital or genetic abnormalities, as well as an improved survival rate among moderately preterm neonates.

Gestational age-specific neonatal mortality in Hong Kong: a population-based retrospective study.

The neonatal period is the most vulnerable period during childhood, with the risk of death being the highest even in developed countries/regions. Hong Kong's neonatal mortality (1‰) is among the world's lowest and has remained similar for 15years. This study aimed to explore neonatal deaths in Hong Kong in detail and determine whether neonatal mortality is reducible at such a low level. Live births in public hospitals in Hong Kong during 01 Jan 2006-31 Dec 2017 were included. Relevant data were extracted from the electronic medical records. Gestational age-specific mortality was calculated, and the trends were analyzed using the Cochran-Armitage trend test. Causes of death were summarized, and risk factors were identified in multivariate logistic regression analysis. In 490,034 live births, 755 cases (1.54‰) died during the neonatal period, and 293 (0.6‰) died during the post-neonatal period. The neonatal mortality remained similar overall (P = 0.17) and among infants born at 24-29weeks' gestation (P = 0.4), while it decreased in those born at 23 (P = 0.04), 30-36 (P < 0.001) and ≥ 37 (P < 0.001) weeks' gestation. Neonates born at < 27weeks' gestation accounted for a significantly increased proportion among cases who died (27.6%to 51.9%), with hemorrhagic conditions (24%) being the leading cause of death. Congenital anomalies were the leading cause of death in neonates born ≥ 27weeks' gestation (52%), but its cause-specific mortality decreased (P = 0.002, 0.6‰ to 0.41‰), with most of the decrease attributed to trisomy 13/18 and multiple anomalies. Reduction of neonatal mortality in developed regions may heavily rely on improved quality of perinatal and neonatal care among extremely preterm infants.

Nationwide Birth Weight and Gestational Age-specific Neonatal Mortality Rate in Taiwan

There are limited nationwide data relating to neonatal mortality rate in Taiwan. This study aims to provide updated national birth weight/gestational age-specific neonatal mortality reference rates. We abstracted the birth registration database from the Ministry of Interior in Taiwan from 1998 to 2002 and linked the data to the death registration database from the Ministry of Health and Welfare in Taiwan between 1998 and 2003. We included 1,331,785 infants born between 20 weeks and 44 weeks of gestation and weighing within the median ± 2 interquartile ranges in their age group in this study. We calculated the birth weight/gestational age-specific neonatal mortality rates of different genders by birth weight increments of 250g and at gestational age intervals of 1 week. A Poisson regression model was used in modeling the mortality data. A total of 4,169 deaths occurred within 28 days of life out of a total of 1,331,785 live births between 20 weeks and 44 weeks of gestation, giving a neonatal mortality rate (0-27 days) of 3.39 per 1000 live births for males and 2.80 per 1000 for females. The infant mortality rate remained higher in the male (5.91 per 1000) than the female (5.10 per 1000) population within the 1(st) year of life. Birth weight/gestational age-specific neonatal mortality rates were plotted with curves representing the 10(th) and 90(th) birth weight percentiles. The risk of an early neonatal death (0-6 days) does not exceed 50% except for female neonates<500g and ≤ 23 weeks, which implies that the limit of viability is now at 23 weeks for females. We have provided an easy-to-use birth weight/gestational age-specific neonatal mortality rate chart as a reference document that physicians and parents can use to make decisions based on ethical considerations relating to whether to give palliative care or further invasive management. The normative data are crucial for public health policies on neonatal care in Taiwan.

Gestational Age Patterns of Fetal and Neonatal Mortality in Europe: Results from the Euro-Peristat Project

BackgroundThe first European Perinatal Health Report showed wide variability between European countries in fetal (2.6–9.1‰) and neonatal (1.6–5.7‰) mortality rates in 2004. We investigated gestational age patterns of fetal and neonatal mortality to improve our understanding of the differences between countries with low and high mortality.Methodology/Principal FindingsData on 29 countries/regions participating in the Euro-Peristat project were analyzed. Most European countries had no limits for the registration of live births, but substantial variations in limits for registration of stillbirths before 28 weeks of gestation existed. Country rankings changed markedly after excluding deaths most likely to be affected by registration differences (22–23 weeks for neonatal mortality and 22–27 weeks for fetal mortality). Countries with high fetal mortality ≥28 weeks had on average higher proportions of fetal deaths at and near term (≥37 weeks), while proportions of fetal deaths at earlier gestational ages (28–31 and 32–36 weeks) were higher in low fetal mortality countries. Countries with high neonatal mortality rates ≥24 weeks, all new member states of the European Union, had high gestational age-specific neonatal mortality rates for all gestational-age subgroups; they also had high fetal mortality, as well as high early and late neonatal mortality. In contrast, other countries with similar levels of neonatal mortality had varying levels of fetal mortality, and among these countries early and late neonatal mortality were negatively correlated.ConclusionsFor valid European comparisons, all countries should register births and deaths from at least 22 weeks of gestation and should be able to distinguish late terminations of pregnancy from stillbirths. After excluding deaths most likely to be influenced by existing registration differences, important variations in both levels and patterns of fetal and neonatal mortality rates were found. These disparities raise questions for future research about the effectiveness of medical policies and care in European countries.

Incidence-based measures of birth, growth restriction, and death can free perinatal epidemiology from erroneous concepts of risk

Background Traditional perinatal epidemiology appears to embrace fallacious concepts of risk. The use of incorrect denominators for perinatal rates is commonplace both for straightforward indices such as the gestational age–specific labor induction rate and also for the more conceptually challenging indices such as the gestational age–specific neonatal mortality rate. As a consequence, perinatology is beset by several conondrums including the paradox of intersecting perinatal mortality curves. Proposition These traditions are ideally replaced by alternative concepts that may be derived a priori and measured using indices such as presented here: the incidence of birth (i.e., the gestational age–specific birth rate), the incidence of growth restriction (i.e., the gestational age–specific growth-restriction rate) and the incidence of death (i.e., the age–specific mortality rate). Results The incidence of birth, growth restriction, and death quantify the core phenomena in perinatology and reveal congruent and coherent patterns of occurrence. Conclusions These new indices can free perinatal epidemiology from erroneous concepts of risk and resolve the paradoxal phenomena that plague the perinatal domain. They also permit the development of a theoretical framework for obstetric intervention, which in recent years has been based exclusively on empirical evidence.

Gestational age-specific neonatal mortality among preterm singleton births in a Nigerian tertiary institution

This study showed that the limit of viability in our own setting is 28 weeks’ gestation and that neonatal mortality is much higher at all gestational ages than that reported from developed countries. The difference was probably a reflection of the standard of available health facilities. Establishment of regional neonatal centers with improvement in neonatal support facilities will help reduce the current high neonatal mortality rate. (excerpt)

Glycemic control in the diabetic pregnancy: is tighter always better?

Glucose is the principal nutrient that the mother supplies to the fetus through the placenta by way of concentration-dependent mechanisms. In the presence of maternal hypoglycemia, with limited glucose supply, fetal hypoglycemia and hypoinsulinism ensue. This may be viewed as an adaptive mechanism to increase the chances of fetal survival in the face of limited maternal supply, albeit of a growth-restricted fetus. Fetal nutrient deprivation and the resulting hypoinsulinism may have both short- and long-term consequences. Intrauterine growth failure is associated with higher rates of gestational age-specific neonatal mortality and with long-term cognitive deficits. Furthermore, epidemiologic data suggest that diabetes, coronary artery disease, and hypertension are more common among adults who were small for gestational age at birth. Thus, pancreatic failure in adulthood may be either a response to excessive exposure to glucose as a result of maternal hyperglycemia, or as a result of hypoglycemia where nutrient deprivation leads to fetal growth restriction and reduced islet cell proliferation. Because low mean concentrations of maternal glucose in gestational diabetes are associated with an increased risk of fetal growth restriction, overzealous glycemic control during pregnancy may raise concerns regarding the possible effects on the infant. In the mother with Type 1 diabetes, strict glycemic control is often associated with an increased incidence of severe hypoglycemia. Up to 40% of women report at least one episode of severe hypoglycemia during pregnancy, requiring assistance by another person or professional intervention. It is quite possible that in some patients striving to optimize pregnancy outcome by maintaining the best possible glycemic control jeopardizes the well-being of the mother and the fetus. Thus, with respect to tight glycemic control of pregnant women with diabetes, the question arises: How tight is too tight? Is there a threshold below which the trade-off in terms of maternal morbidity as well as fetal growth restriction and its consequences outweighs the benefits of preventing the effects of maternal hyperglycemia?

A multicenter study of preterm birth weight and gestational age—specific neonatal mortality

This analysis was performed to present updated neonatal mortality data by age and birth weight for preterm newborns and to demonstrate the influence of plurality, ethnicity, and infant sex on mortality. Preterm birth weight and gestational age-specific mortality rates were compiled from the five centers that participated in the March of Dimes Multicenter Preterm Birth Prevention Project. In each center gestational age was assessed by standardized methods. A birth weight and gestational age-specific mortality chart for preterm births was created with live-birth data. In each birth weight group mortality decreased as the gestational age advanced; for each gestational age group heavier infants had less mortality. Female infants < 29 weeks survived better than male infants, and singletons < 29 weeks survived better than twins. Survival for black preterm newborns was better than that of whites but differences were not significant. Mortality for black term infants was significantly higher. The largest improvement in survival occurred between 25 and 26 weeks. At 30 weeks survival was > 90% and improved < 1% per week thereafter. When compared with rates in previous reports, mortality rates appear to have improved, especially at gestational ages < 29 weeks. These data may be useful in decision-making and in counseling patients at risk for preterm delivery.

477 Birthweight and gestational age specific neonatal mortality rates

477 Birthweight and gestational age specific neonatal mortality rates

Racial differences in pregnancy duration and its implications for perinatal care

The average length of gestation is about 5 days shorter in black populations than in white populations. Although some of this difference is accounted for by higher preterm delivery rates in blacks, the most common gestational week of delivery at term is the 39th in black populations, the 40th in white. Black gestational age specific neonatal mortality is lower than that of whites until the 37th week of gestation, but higher thereafter. These observations suggest the hypothesis that complications of postmaturity occur sooner in black fetuses. If this hypothesis is confirmed, antepartum surveillance for signs of fetal compromise should be initiated earlier in gestation in black parturients, perhaps by setting the estimated date of confinement at 275 days after the LMP, rather than the conventional 280 days.

Prenatal Care Utilization: Its Measurement and Relationship to Pregnancy Outcome

This study proposes a redesigned measure of prenatal care utilization based on modifications made to a preexisting index of the adequacy of such care. Six prenatal care utilization groups were delineated: intensive, adequate, intermediate, inadequate, no-care, and missing/unknown. Using 430,349 cases from South Carolina and North Carolina vital records from 1978 to 1982 (live birth-infant death cohort files for white resident mothers), this proposed prenatal care utilization measure was examined by maternal sociomedical risk characteristics (age-parity, marital status, education, complications of pregnancy, and previous pregnancy terminations) and by pregnancy outcomes (birth weight, gestational age, and birth weight- and gestational age-specific neonatal mortality). The intensive prenatal care group had relatively more pregnancy complications but also the most preferred pregnancy outcomes. Appreciable differences in birth weight and gestational age distributions were observed among the prenatal care categories within maternal risk status groups. Increased utilization of prenatal care was associated with higher mean birth weight and gestational age. However, after controlling for maternal risk status, an appreciable variation in birth weight- and gestational age-specific neonatal mortality was not apparent across prenatal care groups.

Racial Disparities in Pregnancy Outcomes: The Role of Prenatal Care Utilization and Maternal Risk Status

Distinct black-white differences in pregnancy outcome and prenatal care utilization have been a persistent feature of U.S. natality-related statistics. Using South Carolina and North Carolina live birth-infant death cohort files for 1978-1982, this study examines the extent to which variations in prenatal care utilization may be associated with racial disparities in pregnancy outcome within maternal sociomedical risk groups. After taking indicators of maternal risk into account (age-parity, education, marital status, complications of pregnancy and previous pregnancy terminations), birth weight and gestational age distributions and birth weight- and gestational age-specific neonatal mortality rates of blacks and whites were compared by level of prenatal care utilization. Distinct racial differences in birth weight and gestational age distributions were observed within equivalent maternal risk and prenatal care categories, with whites having an approximately 200-gram mean birth weight and five-day mean gestational age advantage compared to blacks. In this analysis of more than 650,000 cases, low-risk blacks adequately utilizing prenatal care had a lower mean birth weight (3,266 grams) and a higher neonatal mortality rate (6.6) than low-risk, inadequate-care whites (3,302 grams; 6.1).