Correlation of Maternal BMI with Foetal Liver Blood Flow and Neonatal Adiposity in Normal Pregnancies and Pregnancies Complicated by Gestational Diabetes Mellitus and Foetal Growth Restriction

Abstract

Introduction: The foetus exhibits a wide array of structural and functional adaptations in response to intrauterine conditions, towards protection of vital organs and maintaining the supply of essential nutrients. When oxygen is limited, foetal adaptations prioritise brain growth, irrespective of whether other essential nutrients are limited or not. The hypothesis for this study was that fatty acid synthesis occurs in foetal liver therefore if adaptive changes occur in the hepatic and umbilical flow it will affect fat deposition which will manifest as neonatal adiposity. Aim: Correlation of maternal Basal Metabolic Index (BMI) with Foetal liver blood flow and neonatal adiposity in normal pregnancies and pregnancies complicated by Gestational Diabetes Mellitus (GDM) and Foetal Growth Restriction (FGR) .Materials and Methods: An observational pilot study was carried out in a tertiary care referral hospital of Northern India. Antenatal women were recruited in three groups of singleton uncomplicated pregnancies (40), Women with GDM (31) and women with FGR (29). Maternal characteristics including pre-pregnancy BMI and obstetric ultrasound doppler study were recorded at 35 weeks gestation. The time-averaged maximum velocity (TAMX) was calculated for Umbilical Vein (UV) and Ductus Venosus (DV) as (Vmax) UV and (Vmax) DV. Blood flow (Q) was calculated as Q=h×(D/2)2×p×TAMX. The neonatal biometry and Skin Fold Thickness (SFT) was measured. Statistical techniques used were t-tests for analyses of dichotomous outcomes, Pearson’s correlation (r) and multivariate regression. Results: In mothers with higher DV shunting neonatal adiposity was significantly lower in the FGR group. In the uncomplicated group about 46% of variation in adiposity was explained by all the study variables and overall regression equation was statistically significant (p=0.004). Conclusion: Mothers with low BMI and normal umbilical and middle cerebral doppler flow had higher foetal hepatic flow to improve substrate deposition. DV shunting was significantly higher in hypoxic foetuses with reduced hepatic flow.