[Customized and non-customized French intrauterine growth curves. II - Comparison with existing curves and benefits of customization]

Abstract

Objectives: Our aim is to compare the new French EPOPé intrauterine growth curves, developed to address the guidelines 2013 of the French College of Obstetricians and Gynecologists, with reference curves currently used in France, and to evaluate the consequences of their adjustment for fetal sex and maternal characteristics.

Population and methods: Eight intrauterine and birthweight curves, used in France were compared to the EPOPé curves using data from the French Perinatal Survey 2010. The influence of adjustment on the rate of SGA births and the characteristics of these births was analysed.

Results: Due to their birthweight values and distribution, the selected intrauterine curves are less suitable for births in France than the new curves. Birthweight curves led to low rates of SGA births from 4.3 to 8.5% compared to 10.0% with the EPOPé curves. The adjustment for maternal and fetal characteristics avoids the over-representation of girls among SGA births, and reclassifies 4% of births. Among births reclassified as SGA, the frequency of medical and obstetrical risk factors for growth restriction, smoking (≥10 cigarettes/day), and neonatal transfer is higher than among non-SGA births (P<0.01).

Conclusion: The EPOPé curves are more suitable for French births than currently used curves, and their adjustment improves the identification of mothers and babies at risk of growth restriction and poor perinatal outcomes.

Keywords: Ajustement; Birthweight; Courbes de croissance in utero; Customisation; Fetal growth restriction; Intra-uterine growth curves; Petit poids pour l’âge gestationnel; Poids de naissance; Retard de croissance intra-utérin; Small for gestational age.