Objective To determine whether customised birthweight standard improves the de®nition of small for gestational age and its association with adverse pregnancy outcomes such as stillbirth, neonatal death, or low Apgar score.Design Population based cohort study. Population Births in Sweden between 1992-95 (n 326,377).Methods Risks of stillbirth, neonatal death, and Apgar score under four at ®ve minutes were calculated for the lowest 10% birthweights according to population-based and customised standards, and were compared with the data from the group with birthweights over this limit. Population attributable risks for stillbirth using various birthweight centile cutoffs were calculated for the two standards. Outcome measures Odds ratios and 95% con®dence intervals for stillbirth, neonatal death and Apgar score under four at ®ve minutes, and population attributable risks for stillbirth at different birthweight centiles. Results Risks of stillbirth, neonatal death, and Apgar score under four at ®ve minutes and population attributable risks of stillbirth were consistently higher if`small for gestational age' was classi®ed by a customised rather than by the population-based birthweight standard. Compared with infants who were not small for gestational age by both standards, the odds ratio for stillbirth was 6.1 (95% CI 5.0-7.5) for small for gestational age by customised standard only, whereas it was 1.2 (95 % CI 0.8-1.9) for small for gestational age by population standard only. Conclusions Compared with the population-based birthweight standard, a customised birthweight standard increases identi®cation of fetuses at risk of stillbirth, neonatal death and Apgar score under 4 at 5 minutes, probably due to improved identi®cation of fetal growth restriction.
Objective To determine the relative importance of genetic effects on birthweight, gestational length and small for gestational age. Design A cohort study, using individual record linkage between the population‐based Swedish Twin and Birth Registers to estimate twin similarities in twins with known zygosity. Population Included were 868 monozygotic and 1141 dizygotic female twin pairs, born in Sweden before 1959, who both delivered single births from 1973–1993. Methods Quantitative genetic methods, offspring birthweight, gestational length and small for gestational age birth in twin sisters. Main outcome measures Twin similarities measured as probandwise concordance rates and intra‐class correlations for birthweight, gestational length and small for gestational age births. Results Concordance rates and intra‐class correlations for birthweight, gestational length and small for gestational age were consistently higher in monozygotic compared with dizygotic twins. Model fitting suggested heritability estimates in the range from 25% to 40%. Conclusions This study suggests genetic effects not only for birthweight and fetal growth, but also for gestational length. The mediation of these genetic effects may partly be due to similarities in maternal antropometric measures, lifestyle and medical complications during pregnancy. The study does not distinguish between fetal and maternal genetic effects.
Objective We wanted to compare customised and population standards for defining smallness for gestational age (SGA) in the assessment of perinatal mortality risk associated with parity and maternal size.Design Population-based cohort study.Setting Sweden.Population Swedish Birth Registry database 1992-1995 with 354 205 complete records.Method Coefficients were derived and applied to determine SGA by the fully customised method, or by adjustment for fetal sex only, and using the same fetal weight standard.Main outcome measure Perinatal deaths and rates of small for gestational age (SGA) babies within subgroups stratified by parity, body mass index (BMI) and maternal size within the BMI range of 20.0-24.9.Results Perinatal mortality rates (PMR) had a U-shaped distribution in parity groups, increased proportionately with maternal BMI, and had no association with maternal size within the normal BMI range. For each of these subgroups, SGA rates determined by the customised method showed strong association with the PMR. In contrast, SGA based on uncustomised, populationbased centiles had poor correlation with perinatal mortality. The increased perinatal mortality risk in pregnancies of obese mothers was associated with an increased risk of SGA using customised centiles, and a decreased risk of SGA using population-based centiles.Conclusion The use of customised centiles to determine SGA improves the identification of pregnancies which are at increased risk of perinatal death.Keywords Body mass index, customised centiles, fetal growth restriction, intrauterine growth restriction, maternal size, parity, perinatal mortality, small for gestational age.Please cite this paper as: Gardosi J, Clausson B, Francis A. The value of customised centiles in assessing perinatal mortality risk associated with parity and maternal size.
Objective To determine whether customised birthweight standard improves the de®nition of small for gestational age and its association with adverse pregnancy outcomes such as stillbirth, neonatal death, or low Apgar score.Design Population based cohort study.Population Births in Sweden between 1992-95 (n 326,377).Methods Risks of stillbirth, neonatal death, and Apgar score under four at ®ve minutes were calculated for the lowest 10% birthweights according to population-based and customised standards, and were compared with the data from the group with birthweights over this limit. Population attributable risks for stillbirth using various birthweight centile cutoffs were calculated for the two standards. Outcome measures Odds ratios and 95% con®dence intervals for stillbirth, neonatal death and Apgar score under four at ®ve minutes, and population attributable risks for stillbirth at different birthweight centiles. Results Risks of stillbirth, neonatal death, and Apgar score under four at ®ve minutes and population attributable risks of stillbirth were consistently higher if`small for gestational age' was classi®ed by a customised rather than by the population-based birthweight standard. Compared with infants who were not small for gestational age by both standards, the odds ratio for stillbirth was 6.1 (95% CI 5.0-7.5) for small for gestational age by customised standard only, whereas it was 1.2 (95 % CI 0.8-1.9) for small for gestational age by population standard only. Conclusions Compared with the population-based birthweight standard, a customised birthweight standard increases identi®cation of fetuses at risk of stillbirth, neonatal death and Apgar score under 4 at 5 minutes, probably due to improved identi®cation of fetal growth restriction.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.