Endocrine Abstracts

Background: Previous studies use small for gestational age (SGA) as a surrogate marker for fetal growth restriction (FGR). SGA individuals, particularly those who show catch-up growth have greater cardiometabolic (CM) risk than those born appropriate for gestational age. However, not all FGR fetuses are born SGA. Therefore, we studied neonates born following pregnancies at increased risk of FGR, irrespective of birthweight.

Aim: To define associations between fetal weight trajectory and postnatal weight and adiposity trajectories from birth to six months.

Methods: Participants were recruited from a specialist clinic of women considered at increased risk of FGR, based on maternal antenatal serology (pregnancy associated plasma protein-A <0.415 multiples of the median (MoM), alpha fetoprotein >2.2 MoM or inhibin A >2 MoM). Births <34 weeks’ gestation were excluded. Measurements were taken for weight, length, mid-upper arm circumference (MUAC), abdominal circumference (AC), thigh circumference (TC), and biceps, triceps and subscapular skinfold thicknesses. Body mass index (BMI, weight(kg)/(height(m))²) and the sum of skinfolds (sum SF, mm) were calculated. ΔfetalC ([birthweight centile minus 23 week estimated fetal weight centile]/days) and postnatally, ΔweightC ([six-month weight centile minus birthweight centile]/days), as well as ΔBMI, sum SF, MUAC, AC and TC were calculated. Pearson’s product moment correlation coefficient (parametric) and Kendall’s tau (non-parametric) were used to determine correlations between ΔfetalC and ΔweightC, BMI, sum SF, MUAC, AC and TC.

Results: Of 42 participants with ΔBMI data available, 36 (81%) had a negative ΔfetalC, but only 3 (7%) were born SGA. ΔfetalC correlated negatively with ΔBMI (r=-0.38, P=0.012), sum SF (r=-0.36, P=0.016, n=43), MUAC (r=-0.32, P=0.034, n=44) and AC (r=-0.30, P=0.045, n=44), but not with ΔweightC or TC.

Conclusions: ΔfetalC was negatively linked with postnatal markers of adiposity in early life, highlighting inadequate fetal weight gain as an indicator of accelerated postnatal adiposity. Only a small proportion were SGA, suggesting that FGR should be considered an independent risk factor for CM risk. The absence of an association between ΔfetalC and ΔweightC demonstrates the value in monitoring adiposity changes in the first six months. Therefore, routine postnatal length measurements to calculate BMI are necessary.