Endocrine Abstracts

Background: Using small for gestational age (SGA) as a surrogate for fetal growth restriction, previous studies link adverse intrauterine environments to greater cardiometabolic risk. However, a fetus may undergo suboptimal fetal growth (SFG) without being SGA. The Manchester BabyGRO Study focused on recruiting pregnancies at greater risk of SFG, including pregnancies with low PAPP-A, where a pattern of reduced skeletal growth has been described(1). Associations were explored between fetal weight centile and postnatal indicators of accelerated/ catch-up growth, other potential fetal indicators of postnatal adiposity trajectory were not explored.

Aim: Investigate relationships between segmental growth trajectories and central adiposity in fetal and postnatal life.

Methods: Components of the Hadlock formula used to calculate estimated fetal weight (EFW) in the Manchester BabyGRO Study were: head circumference (HC), abdominal circumference (AC), and femur length (FL). AC was selected as a marker of central adiposity; FL as a marker of skeletal growth. Δfetal_AC ([birth AC minus 23 week AC]/days), 23 week fetal FL, and postnatally Δ0-3_AC ([three-month AC minus birth AC]/days), Δ0-6_AC, Δ0-12_AC, Δ0-3_leg ([three-month leg length minus birth leg length]/days), Δ0-6_leg and Δ0-12_leg were calculated. Parametric data were assessed using Pearson’s correlation, Spearman’s correlations assessed non-parametric data to determine significant correlations between fetal and postnatal trajectories, P value <0.05 was considered significant.

Results: 78/80 participants had estimated fetal biometry <200 days’ gestation (39/78 male offspring), 59%/15%/12% White/ Asian/ Black and 14% other ethnicity, Δfetal_AC correlated negatively with Δ0-3_AC (r=−0.453, P<0.001) and Δ0-6_AC (r=−0.540, P<0.001), but not with Δ0-12_AC (r=−0.16, P=0.330). No correlations were observed between ultrasound femur length and postnatal leg length trajectories.

Conclusion: Relationships between fetal and postnatal AC trajectories suggest Δfetal_AC may represent a fetal marker of undesirable postnatal adiposity trajectory. Associations between pre- and postnatal skeletal measures were not detected. Postnatal femur length measurements would allow for direct comparisons and add value to future studies.

1. Thurlwell, Z.-R. (2021) Reproducibility and Accuracy of 2D and 3D Ultrasound Parameters In The Prediction of Birthweight In Pregnancies With Low Serum PAPP-A. Thesis.