[Customized and non-customized French intrauterine growth curves. I - Methodology]

We developed intrauterine growth references, called EPOPé curves, in line with recommendations for screening of intra-uterine growth restriction issued in 2013 by the French College of Obstetricians and Gynecologists.

Using the French Perinatal Survey (FPS) 2010, we adapted the methodology developed by Gardosi (1) to model intrauterine growth and its distribution and (2) to adjust for physiological fetal and maternal factors influencing fetal weight. Based on this model, 3 reference curves (unadjusted, adjusted for fetal sex, and adjusted for fetal sex, and maternal height, weight and parity) were proposed. We applied these models to births in the 2010 FPS and the French hospital discharge database (PMSI) in 2011-2012.

Among singleton live births in the FPS and the PMSI, the model adjusted for fetal sex identified 3.2 and 3.3% of births below the 3rd centile respectively, and 10.0 and 10.2% below the 10th. In model adjusted for maternal factors, 4.0% of births from the FPS 2010 were reclassified, but population rates remained at 3.0 and 10.0%.

This growth model is appropriate for French births, and allows for the implementation of a homogeneous definition of small for gestational age infants during pregnancy and at birth.