Performance of six birth-weight and estimated-fetal-weight standards for predicting adverse perinatal outcome: a 10-year nationwide population-based study.

OBJECTIVE: To evaluate three birth-weight (BW) standards (Australian population-based, Fenton and INTERGROWTH-21st ) and three estimated-fetal-weight (EFW) standards (Hadlock, INTERGROWTH-21st and WHO) for classifying small-for-gestational age (SGA) and large-for-gestational age (LGA) and predicting adverse perinatal outcomes in preterm and term babies. METHODS: This was a nationwide population-based study conducted on a total of 2.4 million singleton births that occurred from 24 + 0 to 40 + 6 weeks' gestation between 2004 and 2013 in Australia. The performance of the growth charts was evaluated according to SGA and LGA classification, and relative risk (RR) and diagnostic accuracy based on the areas under the receiver-operating-characteristics curves (AUCs) for stillbirth, neonatal death, perinatal death, composite morbidity and a composite of perinatal death and morbidity outcomes. The analysis was stratified according to gestational age at delivery (< 37 + 0 vs ≥ 37 + 0 weeks). RESULTS: Following exclusions, 2 392 782 singleton births were analyzed. There were significant differences in the SGA and LGA classification and risk of adverse outcomes between the six BW and EFW standards evaluated. For the term group, compared with the other standards, the INTERGROWTH-21st BW and EFW standards classified half the number of SGA (< 10th centile) babies (3-4% vs 7-11%) and twice the number of LGA (> 90th centile) babies (24-25% vs 8-15%), resulting in a smaller cohort of term SGA at higher risk of adverse outcome and a larger LGA cohort at lower risk of adverse outcome. For term SGA (< 3rd centile) babies, the RR of perinatal death using the two INTERGROWTH-21st standards was up to 1.5-fold higher than those of the other standards (including the WHO-EFW and Hadlock-EFW), while the INTERGROWTH-21st -EFW standard indicated a 12-26% reduced risk of perinatal death for LGA cases across centile thresholds. Conversely, for the preterm group, the WHO-EFW and Hadlock-EFW standards identified a higher SGA classification rate than did the other standards (18-19% vs 10-11%) and a 20-65% increased risk of perinatal death in term LGA babies. All BW and EFW charts had similarly poor performance in predicting adverse outcomes, including the composite outcome (AUC range, 0.49-0.62) for both preterm (AUC range, 0.58-0.62) and term (AUC range, 0.49-0.50) cases and across centiles. Furthermore, specific centile thresholds for identifying adverse outcomes varied markedly by chart between BW and EFW standards. CONCLUSIONS: This study addresses the recurrent problem of identifying fetuses at risk of morbidity and perinatal mortality associated with growth disorders and provides new insights into the applicability of international growth standards. Our findings of marked variation in classification and the similarly poor performance of prescriptive international standards and the other commonly used standards raise questions about whether the prescriptive international standards that were constructed for universal adoption are indeed applicable to a multiethnic population such as that of Australia. Thus, caution is needed when adopting universal standards for clinical and epidemiological use. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

High burden of RSV hospitalization in very young children: a data linkage study.

Linked administrative population data were used to estimate the burden of childhood respiratory syncytial virus (RSV) hospitalization in an Australian cohort aged <5 years. RSV-coded hospitalizations data were extracted for all children aged <5 years born in New South Wales (NSW), Australia between 2001 and 2010. Incidence was calculated as the total number of new episodes of RSV hospitalization divided by the child-years at risk. Mean cost per episode of RSV hospitalization was estimated using public hospital cost weights. The cohort comprised of 870 314 children. The population-based incidence/1000 child-years of RSV hospitalization for children aged <5 years was 4·9 with a rate of 25·6 in children aged <3 months. The incidence of RSV hospitalization (per 1000 child-years) was 11·0 for Indigenous children, 81·5 for children with bronchopulmonary dysplasia (BPD), 10·2 for preterm children with gestational age (GA) 32-36 weeks, 27·0 for children with GA 28-31 weeks, 39·0 for children with GA <28 weeks and 6·7 for term children with low birthweight. RSV hospitalization was associated with an average annual cost of more than AUD 9 million in NSW. RSV was associated with a substantial burden of childhood hospitalization specifically in children aged <3 months and in Indigenous children and children born preterm or with BPD.

Monitoring fetal and infant survival using regional birth notification data in north east London.

OBJECTIVE: To demonstrate the use of aggregated, locally collected birth notification data to examine trends in birth-weight specific survival for singleton and multiple births. DESIGN: Retrospective analysis of 171,527 notified births and subsequent infant survival data derived from computerised community child health records. Validation of data completeness and quality was undertaken by comparison with birth and death registration records for the same period. SETTING: Notifications of births in 1989-1991 to residents of the North Thames (East) Region (formerly North East Thames Regional Health Authority). OUTCOME MEASURES: Birthweight specific stillbirth, neonatal, and postneonatal death rates. RESULTS: There was close correspondence between the notification and registration data. For 96% of the registered deaths a birth notification record was identified and for the majority of these the death was already known to the Community Child Health Computer. Completeness of birth-weight data, particularly at the lower end of the range, was substantially better in birth notification data. Comparison with the most recent published national data relating to birthweight specific survival of very low birthweight singleton and multiple births suggests that the downward trend of mortality is continuing, at least in this Region. CONCLUSIONS: The use of routinely collected aggregated birth notification data provides a valuable adjunct to existing sources of information about perinatal and infant survival, as well as other information regarding process and outcome of maternity services. Such data are required for comparative audit and may be more complete than that obtained from registration or hospital generated data.

Prolonged pregnancy: evaluating gestation-specific risks of fetal and infant mortality.

OBJECTIVE: To evaluate gestation-specific risks of stillbirth, neonatal and post-neonatal mortality. DESIGN: Retrospective analysis of 171,527 notified births (1989-1991) and subsequent infant survival at one year, from community child health records. SETTING: Notifications from maternity units in the North East Thames Region, London. MAIN OUTCOME MEASURES: The incidence of births, stillbirths, neonatal and post-neonatal deaths at each gestation after 28 completed weeks. Mortality rates per 1000 total or live births and per 1000 ongoing pregnancies at each gestation were calculated. RESULTS: The rates of stillbirth at term (2.3 per 1000 total births) and post-term (1.9 per 1000 total births) were similar. When calculated per 1000 ongoing pregnancies, the rate of stillbirth increased six-fold from 0.35 per 1000 ongoing pregnancies at 37 weeks to 2.12 per 1000 ongoing pregnancies at 43 weeks of gestation. Neonatal and post-neonatal mortality rates fell significantly with advancing gestation, from 151.4 and 31.7 per 1000 live births at 28 weeks, to reach a nadir at 41 weeks of gestation (0.7 and 1.3 per 1000 live births, respectively), increasing thereafter in prolonged gestation to 1.6 and 2.1 per 1000 live births at 43 weeks of gestation. When calculated per 1000 ongoing pregnancies, the overall risk of pregnancy loss (stillbirth + infant mortality) increased eight-fold from 0.7 per 1000 ongoing pregnancies at 37 weeks to 5.8 per 1000 ongoing pregnancies at 43 weeks of gestation. CONCLUSION: The risks of prolonged gestation on pregnancy are better reflected by calculating fetal and infant losses per 1000 ongoing pregnancies. There is a significant increase in the risk of stillbirth, neonatal and post-neonatal mortality in prolonged pregnancy. This study provides accurate data on gestation-specific risks of pregnancy loss, enabling pregnant women and their carers to judge the appropriateness of obstetric intervention.

Relation of maternal ethnicity to infant birthweight in east London, England.

OBJECTIVE: We sought to determine whether black race is a risk factor for very low birthweight in a developed country other than the United States. DESIGN: A cross-sectional study was performed. SETTING: We analyzed a dataset of 1987-1990 birth records from three hospitals in East London, England. PARTICIPANTS: All live born African (N = 3,495), West Indian (N = 3,471), and European white (N = 20,313) singleton infants born to East London residents. MAIN OUTCOME MEASURES: For each ethnic group, we calculated the proportion of very low birthweight (< 1500g) and moderately low birthweight (1500-2499g) infants. RESULTS: The very low birthweight rate was 2.9% for infants of West Indian descent and 2.2% for infants of African descent vs. 1.3% for European whites; odds ratio (95% confidence interval) = 2.1(1.7-2.8) and 1.8(1.2-3.1), respectively. West Indian and white mothers were similar in terms of age, social support, and prenatal care. African mothers were older and had less social support. The West Indian:white and African:white differentials in very low birthweight rates persisted among low risk mothers; odds ratio (95% confidence interval) = 2.7(1.7-4.0) and 2.3(1.5-3.6), respectively. CONCLUSIONS: We conclude that black race is a risk factor for very low birthweight in the United Kingdom.