Endocrine Abstracts

Introduction: Cardiometabolic disease risk is related to small (SGA) or large-for-gestational-age (LGA). Previously, we demonstrated suboptimal fetal growth without SGA is related to adverse risk (BSPED 2022, OC6.2). The multi-site UK Pregnancies Better Eating and Activity Trial (UPBEAT, n = 1,555) had randomised pregnant women with obesity (BMI ≥30 kg/m²) into a pregnancy lifestyle intervention. UPBEAT infants provide an ideal cohort to examine excessive fetal growth and infant health markers.

Aims: 1) Define fetal weight trajectories (Δfetalwt) within the Manchester UPBEAT participants. 2) Assess relationships between Δfetalwt and postnatal adiposity markers at six months.

Methods: Retrospective data from 20-week scans were used to calculate estimated fetal weight (EFW) and centiles. Fetal weight trajectory was calculated as WHO birthweight centile minus WHO EFW centile, divided by the number of days in between. Using available data from the 6-month UPBEAT postnatal study, Pearson’s and Spearman’s rank tests were performed in R version 4.5, to assess correlations between Δfetalwt and 6-month weight, BMI, abdominal circumference (AC) and biceps, triceps and sum of skinfold thicknesses (SDS).

Results: Median maternal booking BMI and gestational weight gain were 35 kg/m² (range 30 to 60) and 7 kg (-1 to 23). 35/124 infants (28%) had participated postnatally, comprising 57% females, 66% appropriate-for-gestational-age, 20% LGA (>90th centile) and 14% SGA (<10th centile). 80% were White, 9% South Asian and 6% Black, and half were breastfed. 25/35 (71%) had a positive Δfetalwt, with no difference between UPBEAT control (mean 0.08 (SD 0.3)) and intervention (mean 0.07 (0.3)) groups. Δfetalwt correlated with 6-month AC SDS (r = 0.37, P = 0.046), and a trend towards significance was observed with 6 m weight SDS (r = 0.32, P = 0.072), but not with 6 m BMI SDS nor any other 6 m measures. When LGA-born infants were excluded, Δfetalwt correlated with 6 m AC SDS (r = 0.42, P = 0.031, n = 26) alone. A trend was observed when LGA and SGA-born were excluded (r = 0.39, P = 0.067, n = 23).

Conclusion: In this Manchester subset of UPBEAT participants, greater Δfetalwt was associated with larger AC SDS, even in the absence of LGA. Including data from other UPBEAT sites could help establish relationships between excessive fetal weight gain and postnatal adiposity markers in infants born appropriate-for-gestational-age.