Definition of Fetal Growth Restriction According to Constitutional Growth Potential

Abstract

Identification of newborn babies with fetal growth restriction remains a problem both from the multi-factorial aspect of fetal growth and from statistical definition. Besides the usual terms: ‘Small for gestational age’ (SGA) and intrauterine growth retardation (IUGR), often used synonymously, the term ‘fetal growth retardation’ was recently introduced in reference to the genetic growth potential of infants. From a sample of 72,000 births, we have designed a statistical model in order to estimate the expected birth weight taking into account gestational age, sex, birth rank, maternal age, height and pregravid weight, we then calculated an individual limit of birth weight under that a newborn must be considered as having a ‘fetal growth restriction’ quoted FwGR. This new approach allowed us to identify 2 groups of newborns with FGR, one classically identified as SGA (noted FwGR_I) (3.9%), and the other newly identified as FGR (noted FwGR_II) (1.4%). In contrast, this approach allowed us to identify a group of ‘constitutionally small’ infants according to their constitutional growth potential (1.1%). In other words, among infants usually defined as SGA (5%), 22% appeared in fact to be ‘constitutionally small’ and therefore misclassified. As an initial validation, we observed that the proportion of maternal hypertension during pregnancy was low in the ‘constitutionally small’ infants (close to that of the normal group), and three times higher in the newly identified group FwGR_II than in the normal group. Following these results, it seems to be meaningful to follow-up this new group of FwGR_II infants, in terms of catch-up growth and neurodevelopmental outcome.

Pre- Pregnancy Weight and Fetal Growth Moroccan Data

“…Edwards et al [1] demonstrated in a study comparing two groups of teenagers whose high BMI divided according to weight gain pergestationnel that macrosomia was significantly more frequent when weight gain exceeded 8 kg during pregnancy; our results confirm this study and is widely approved by Boyd et al [16] how showed that the risk of macrosomia increases markedly with excessive weight gain in addition an earlier study on a Chinese population. [17] that has largely proved the risk of the occurrence of macrosomia was two fold for women who gain more weight during pregnancy then Kabali et al [15] affirmed that fetal macrosomia was significantly higher among women who gained excessive gestational weight.…”

“…[1] Conversely, women who in late pregnancy less than 50 kg and / or a body mass index less than 20 kg/m2 have weight newborns with weight, height and head circumference have relatively increased risk of having a newborn with a delay of intrauterine growth. The weight to gain during pregnancy in industrialized countries is an important factor associated with fetal growth.…”

Mediterranean diet adherence during pregnancy and fetal growth: INMA (Spain) and RHEA (Greece) mother–child cohort studies

“…Fetal growth restriction after accounting for growth potential. A customised definition of restricted growth for the newborns of this study was developed taking into account their constitutional characteristics (30,31) . Maternal and newborn characteristics considered a priori were: gestational age in weeks, maternal and paternal height (in cm) and age (in years), maternal pre-pregnancy weight (in kg), primiparous mother and infant sex.…”

Neurodesenvolvimento de lactentes nascidos a termo pequenos para a idade gestacional no segundo mês de vida

“…Não obstante, os termos RCIU e PIG são, com freqüência, utilizados como sinônimos e os mesmos limites estatísticos são utilizados para sua identificação. No entanto, cabe destacar a possibilidade de alguns neonatos PIG serem apenas constitucionalmente pequenos, quando analisados segundo seu potencial genético de crescimento, representando a porção final da curva de distribuição normal 2 . O conceito de neonato PIG é, portanto, de definição estatística e a interpretação de seu desenvolvimento deve considerar esse importante fator.…”