Fetal and maternal factors associated with neonatal adiposity as measured by air displacement plethysmography: A large cross-sectional study

Abstract

Background

There is evidence that the fetal and early postnatal environments play a role in determining the risk of lifetime obesity, diabetes and cardiovascular disease. Neonatal body composition, as a surrogate marker of the in-utero environment, can be reliably and accurately measured by air displacement plethysmography (ADP). Our primary objective was to identify preconception, fetal and maternal factors affecting neonatal body composition.

Methods

This cross-sectional study included 599 term babies born between September and October 2010 at Royal Prince Alfred Hospital, Sydney, Australia. Neonatal body fat percentage (BF%) was measured within 48 h of birth using ADP. Maternal demographic, anthropometric and medical data as well as neonatal gestational age and sex were used to develop a regression model that predicted body composition and birthweight.

Results

The mean (SD) neonatal BF% in our whole population was 9.2(4.4)%. Significant variables in the model for neonatal BF% were neonatal sex, gestational age, maternal ethnicity, gestational weight gain (GWG), pre-pregnancy BMI, parity and maternal hypertension (p < 0.05); together, these explained 19% of the variation in BF%. GDM status was not a significant variable. Neonatal female sex, maternal Caucasian ethnicity and increased gestational weight gain explained the most variation and were most strongly associated with increased BF%.

Conclusions

This study highlights maternal obesity and increased gestational weight gain as two factors that are amenable to intervention as risk factors for newborn adiposity, which is important in the future study of the “developmental origins of health and disease” hypothesis.

Introduction

The “developmental origins of health and disease” hypothesis is predicated upon increasing evidence that the intrauterine environment impacts child health in the perinatal period, childhood and also into adulthood [1]. Body composition at birth is a more sensitive marker of the intrauterine environment than weight alone, and includes fat mass (FM) and fat free mass (FFM) [2]. FFM is metabolically active and relatively stable in-utero, and may reflect genetic effects. FM is more variable and sensitive to factors that affect fetal growth, such as maternal weight and nutritional status [2]. FM can be measured using total body electrical conductivity [3], dual-energy X-ray absorptiometry [4] or air-displacement plethysmography (ADP), the latter now regarded as the neonatal gold standard method for measuring body composition changes [5], [6], [7].

Fetal adiposity, as a surrogate marker for intrauterine growth, is probably a better predictor for subsequent risk of chronic diseases such as obesity, type 2 diabetes and cardiovascular disease, than birthweight alone [8], [9], [10], [11]. Further, untreated obesity and diabetes in girls and young women of reproductive age can perpetuate disease through maternal-fetal, non-genomic transmission [12]. It is now widely acknowledged that obesity, type 2 diabetes and gestational diabetes mellitus (GDM) are in epidemic proportions in both developed and developing countries [13], and it is a public health imperative to prevent this cycle of disease.

The primary aim of this study was to examine the effect of well-known maternal and neonatal factors on neonatal body fat percentage (BF%) as measured by ADP. This may shed light on the “developmental origins of health and disease” hypothesis and identify public health interventions early in life to prevent later obesity.