Abstract
Introduction
The customised birthweight model can be used to improve detection of babies that may be at risk of adverse outcomes associated with abnormal growth, however it is currently used in conjunction with either an intrauterine growth standard or the individualised birthweight ratio (IBR), both of which have significant methodological flaws. Our aim was to investigate the statistical validity of the IBR and attempt to develop a new measurement to represent the appropriateness of an infant’s size at birth that will support clinicians in identifying infants requiring further attention.
Methods
Routinely collected hospital maternity and neonatal data on singleton, term births from a tertiary Australian hospital were extracted for the time period 1998–2009. The relationships between birthweight, customised birthweight and IBR are investigated using correlation, regression analysis and division of births into groups of < 2500 g, 2500–4000 g and > 4000 g. A new measure, the Birthweight Appropriateness Quotient (BAQ), is developed. The utility of the BAQ is compared with IBR and birthweight to identify infants with a composite neonatal morbidity outcome.
Results
Statistical flaws with the IBR due to significant correlation between birthweight and customised birthweight and a heterogenous relationship between these two measurements across the range of birthweight are present. BAQ is uncorrelated with birthweight. Comparison of BAQ and IBR as indicators of adverse neonatal outcome demonstrates that BAQ identifies babies at risk due to their small size and those babies at risk due to inappropriate size.
Conclusions for Practice
BAQ is a customised measurement of an infant’s size free of the statistical flaws experienced by the IBR with the ability to identify at-risk infants.
References
Bada, H. S., Das, A., Bauer, C. R., Shankaran, S., Lester, B., Wright, L. L., et al. (2002). Gestational cocaine exposure and intrauterine growth: Maternal lifestyle study. Obstetrics & Gynecology, 100(5 Pt 1), 916–924.
Bjorstad, A. R., Irgens-Hansen, K., Daltveit, A. K., & Irgens, L. M. (2010). Macrosomia: Mode of delivery and pregnancy outcome. Acta Obstetricia et Gynecologica Scandinavica, 89(5), 664–669. https://doi.org/10.3109/00016341003686099.
Gardosi, J., Chang, A., Kalyan, B., Sahota, D., & Symonds, E. M. (1992). Customised antenatal growth charts. Lancet, 339(8788), 283–287.
Gardosi, J., Clausson, B., & Francis, A. (2009). The value of customised centiles in assessing perinatal mortality risk associated with parity and maternal size. British Journal of Obstetrics & Gynaecology, 116(10), 1356–1363. https://doi.org/10.1111/j.1471-0528.2009.02245.x.
Gardosi, J., Mongelli, M., Wilcox, M., & Chang, A. (1995). An adjustable fetal weight standard. Ultrasound in Obstetrics & Gynecology, 6(3), 168–174. https://doi.org/10.1046/j.1469-0705.1995.06030168.x.
Gibbons, K., Chang, A., Flenady, V., Mahomed, K., Gardener, G., Gray, P. H., et al. (2013). Customised birthweight models: Do they increase identification of at-risk infants? Journal of Paediatrics and Child Health, 49(5), 380–387. https://doi.org/10.1111/jpc.12189.
Hadfield, R. M., Lain, S. J., Simpson, J. M., Ford, J. B., Raynes-Greenow, C. H., Morris, J. M., et al. (2009). Are babies getting bigger? An analysis of birthweight trends in New South Wales, 1990–2005. Medical Journal of Australia, 190(6), 312–315.
Hemkens, L. G., Contopoulos-Ioannidis, D. G., & Ioannidis, J. P. A. (2016). Routinely collected data and comparative effectiveness evidence: promises and limitations. CMAJ, 188(8), E158–E164. https://doi.org/10.1503/cmaj.150653.
Hutcheon, J. A., Zhang, X., Cnattingius, S., Kramer, M. S., & Platt, R. W. (2008). Customised birthweight percentiles: Does adjusting for maternal characteristics matter? BJOG, 115(11), 1397–1404. https://doi.org/10.1111/j.1471-0528.2008.01870.x.
Hutcheon, J. A., Zhang, X., Platt, R. W., Cnattingius, S., & Kramer, M. S. (2011). The case against customised birthweight standards. Paediatric and Perinatal Epidemiology, 25(1), 11–16. https://doi.org/10.1111/j.1365-3016.2010.01155.x.
Ibiebele, I., Coory, M., Smith, G. C., Boyle, F. M., Vlack, S., Middleton, P., et al. (2016). Gestational age specific stillbirth risk among Indigenous and non-Indigenous women in Queensland, Australia: A population based study. BMC Pregnancy Childbirth, 16(1), 159. https://doi.org/10.1186/s12884-016-0943-7.
Ingram, E., Morris, D., Naish, J., Myers, J., & Johnstone, E. (2017). MR imaging measurements of altered placental oxygenation in pregnancies complicated by fetal growth restriction. Radiology, 285(3), 953–960. https://doi.org/10.1148/radiol.2017162385.
Khashan, A. S., & Kenny, L. C. (2009). The effects of maternal body mass index on pregnancy outcome. European Journal of Epidemiology, 24(11), 697–705. https://doi.org/10.1007/s10654-009-9375-2.
Lackman, F., Capewell, V., Richardson, B., daSilva, O., & Gagnon, R. (2001). The risks of spontaneous preterm delivery and perinatal mortality in relation to size at birth according to fetal versus neonatal growth standards. American Journal of Obstetrics & Gynecology, 184(5), 946–953. https://doi.org/10.1067/mob.2001.111719.
Metz, T. D., & Stickrath, E. H. (2015). Marijuana use in pregnancy and lactation: A review of the evidence. American Journal of Obstetrics and Gynecology, 213(6), 761–778. https://doi.org/10.1016/j.ajog.2015.05.025.
Ong, S. S., Moore, R. J., Warren, A. Y., Crocker, I. P., Fulford, J., Tyler, D. J., et al. (2003). Myometrial and placental artery reactivity alone cannot explain reduced placental perfusion in pre-eclampsia and intrauterine growth restriction. BJOG, 110(10), 909–915.
Pereira, P. P., Da Mata, F. A., Figueiredo, A. C., de Andrade, K. R., & Pereira, M. G. (2017). Maternal active smoking during pregnancy and low birth weight in the americas: A systematic review and meta-analysis. Nicotine & Tobacco Research, 19(5), 497–505. https://doi.org/10.1093/ntr/ntw228.
Resnik, R. (2011). To customise or not to customise: That is the question. Paediatric and Perinatal Epidemiology, 25(1), 17–19. https://doi.org/10.1111/j.1365-3016.2010.01156.x.
Sanderson, D. A., Wilcox, M. A., & Johnson, I. R. (1994). Relative macrosomia identified by the individualised birthweight ratio (IBR). A better method of identifying the at risk fetus. Acta Obstetricia et Gynecologica Scandinavica, 73(3), 246–249.
Sharma, D., Farahbakhsh, N., Shastri, S., & Sharma, P. (2016). Intrauterine growth restriction—Part 2. Journal of Maternal-Fetal and Neonatal Medicine, 29(24), 4037–4048. https://doi.org/10.3109/14767058.2016.1154525.
Wilcox, M. A., Johnson, I. R., Maynard, P. V., Smith, S. J., & Chilvers, C. E. (1993). The individualised birthweight ratio: A more logical outcome measure of pregnancy than birthweight alone. British Journal of Obstetrics & Gynaecology, 100(4), 342–347. https://doi.org/10.1111/j.1471-0528.1993.tb12977.x.
Author information
Authors and Affiliations
Corresponding author
Ethics declarations
Conflict of interest
The authors declare no conflicts of interest.
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Gibbons, K.S., McIntyre, H.D., Mamun, A. et al. Development of the Birthweight Appropriateness Quotient: A New Measure of Infant’s Size. Matern Child Health J 24, 1202–1211 (2020). https://doi.org/10.1007/s10995-020-02994-4
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10995-020-02994-4