Can we improve the birth weight prediction? The effect of normal BMI using a multivariate model

Nutr Hosp. 2014 Oct 3;31(3):1345-51. doi: 10.3305/nh.2015.31.3.8150.

Abstract
in English, Spanish

Objective: The construction of a predictive model that improves the estimation of the fetal weight (EFW).

Study design: a comparative, descriptive study. One hundred forty pregnant women were recruited at two-stage sample in health department in Spain. They were classified in four groups depending on the pre-gestational BMI. Fetal weight at term was estimated by ultrasound at 33-35 weeks (EFW40w) by one gynecologist. A regression model was created with the variables that reacted to the newborn's weight, symphysis-fundal height (SFH), EFW40w, gestational age (GA), ferritin level and cigarettes smoked.

Results: A multivariate model was created for the NW group to estimate the fetal weight (EFWme), resulting in R2=0.727 (p<0.001). The differences of the averages obtained between EFW40w and EFWme, with the newborn's weight were significant (p<0.001). EFWme underestimates birth weight by 0.07 g (mean error 0.53%), and EFW40w overestimates it by 300.89 g (mean error 10.12%). In order to evaluate the predictive model and verify the predictions we used the Bland-Altman analysis. The average error in estimating the birth weight with EFWme was 1.94% underestimating the result, whereas the ultrasound error overestimated the result 10.93%.

Conclusion: The multivariate model created for the NW group improves the accuracy of the ultrasound.

Objectivo: construir un modelo predictivo que mejore la estimación del peso del recién nacido (PFE). Material y Métodos: Estudio observacional dónde 140 gestantes fueron estudiadas mediante un muestreo bietápico en un Departamento de Salud en España. Fueron clasificadas en cuatro grupos dependiendo del IMC pregestacional materno. El peso proyectado al nacer fue estimado por la ecografía realizada entre las 33-35 semanas de gestación (PP40s). Se construyó un modelo de regresión con las variables que se reaccionaban con el peso al nacer, altura uterina (AU), PP40s, edad gestacional (EG), nivel de ferritina y cigarillos consumidos. Resultados: Se construyó un modelo multivariante para el grupo Normo-peso para estimar el peso al nacer (PFm) obteniendo una R2=0,727 (p.

Publication types

  • Comparative Study
  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Birth Weight*
  • Body Mass Index*
  • Female
  • Ferritins / blood
  • Fetus / anatomy & histology
  • Forecasting
  • Gestational Age
  • Humans
  • Models, Biological
  • Multivariate Analysis
  • Pregnancy
  • Prospective Studies
  • Pubic Symphysis / anatomy & histology
  • Smoking / epidemiology
  • Socioeconomic Factors
  • Spain
  • Ultrasonography, Prenatal
  • Uterus / anatomy & histology
  • Young Adult

Substances

  • Ferritins