Identification of newborns with Fetal Growth Restriction (FGR) in weight and/or length based on constitutional growth potential

Abstract

This study was carried out to build statistical models for defining FGR (Fetal Growth Restriction) in weight and/or length after taking growth potential of an infant into account. From a cohort of pregnant women having given birth to 47,733 infants in 141 French maternity units, two statistical models gave individualized limits of birth weight and birth length (based on the 5th centile) below which, after adjustment for its individual growth potential, a newborn must be considered as FGR in weight and/or in length. A sample of 906 infants had measures taken of cord blood growth factors (IGF1, IGFBP3). The FGR(W) definition (weight<5th centile for growth potential) permitted the identification of infants who presented rates of maternal hypertension (13.6%) and of Apgar score at 5 min<6 (2.9%) higher than in the classical group SGA(W) (weight<5th centile for sex and gestational age) (9.6% and 2.2% respectively). By combining FGR(W) and SGA(W), a subgroup of infants, not currently recognized as SGA, presented very high rates of maternal hypertension (19.9%) and of low Apgar score (3.9%). Conversely a subgroup of infants, currently recognized as SGA(W), had rates as low as in the normal infants group, and had to be considered as "constitutionally small" (that is to say 24% of the SGA(W)). Combining FGR(W) and FGR(L) (length<5th centile of growth potential), 7.6% of infants appeared growth-restricted, and 1.8% appeared constitutionally small in weight and/or in length. The FGR(W)-FGR(L) infants showed the lowest mean values of IGF1 (126.2+/-3.2) and IGFBP3 (0.86+/-0.03). These new definitions of FGR(W) and FGR(L) could help to better identify infants at birth requiring neonatal care, and monitoring of growth catch-up and neurodevelopmental outcome.

High Birth Weight and Early Postnatal Weight Gain Protect Obese Children and Adolescents From Truncal Adiposity and Insulin Resistance

“…Birth weight and length and weight and height at 2 and 4 years are mandatory information in the French health care system and were retrospectively obtained from the individual health book, a record of growth measurements, vaccinations, and significant health-related events for every child in France (19). Weight at birth was converted into percentiles and SD score for age and sex according to the French customized birth weight curves, Association of Users of Computerized Medical Records in Paediactrics, Obstetrics, and Gynaecology (AUDIPOG) (14), which accounted for maternal age, weight before pregnancy, height, parity, gestational age, and sex. Current weight and height and pubertal stage were assessed.…”

“…To address these questions, we studied 117 obese children and adolescents divided into three groups according to their fetal growth category as determined with French customized birth weight standards (14), after exclusion of maternal diabetes. They were found to be comparable for age, sex, pubertal stage, and percent body fat assessed by dual-energy X-ray absorptiometry: 32 had HBW according to customized standards (HBWcust), 52 were eutrophic, and 33 had LBW according to customized standards (LBWcust).…”

“…First, we excluded HBW due to maternal diabetes, since it may promote larger birth size as well as confer a risk of diabetes to offspring. Second, we used customized birth weight standards (which are adjusted for maternal characteristics and gestation number) instead of population-based standards (adjusted only for gestational age and sex) to identify subjects with true altered fetal growth and distinguish them from constitutionally large infants (14). Finally, the pattern of postnatal weight gain may modulate insulin resistance in obese subjects born with HBW, as we found that high weight gain between 0 and 2 years protected from later insulin resistance whereas high weight gain after 4 years increased insulin resistance.…”

Reduction of IGF-binding protein-3 as a potential marker of intra-uterine growth restriction

“…Their study used two classifications to define growth restriction: 1) a reduction of )20% of the estimated fetal weight from the 22 nd gestational week until birth, based on serial ultrasound scans, and 2) a classification at birth as AGA or SGA using the 10 th percentile of a customized growth chart as a cut-off. Similar to Mamelle et al (2006) w24x, Verkauskiene et al (2007 found AGA babies who were growth restricted and SGA babies who were not growth restricted. In our study, we tried to minimize this difficulty by using a more restricted cut-off to define SGA: birth weight equal to or -2 SD below the mean.…”

“…In a study considering constitutional growth potential based on maternal characteristics, Mamelle et al (2006) demonstrated that the group of infants classically classified as SGA was heterogeneous in respect to having suffered in utero growth restriction: some were SGA by weight and/or length but were in fact not growth restricted w24x. Additionally, some infants, classified as AGA by weight and/or length, had suffered growth restriction w24x.…”