PED NEONAT 20-000599 Fetal Body Composition

1.1 OBJECTIVE This study's goals are to: 1) use free-breathing magnetic resonance imaging (FB-MRI) to measure fetal body composition in the third trimester and 2) determine how the FB-MRI quantitative measurements compare to growth parameters at birth. 1.2 HYPOTHESES AND SPECIFIC AIMS To accomplish the investigators' objectives, the aims and hypotheses are as follows: Specific Aim 1: In a prospective study in women with healthy pregnancies and women with fetuses that have intrauterine growth restriction (IUGR) and gestational diabetes, the investigators will quantify fetal subcutaneous, visceral, and brown adipose tissue volumes and proton-density fat fraction (PDFF) using FB-MRI in the third trimester. Hypothesis 1: Using a FB-MRI technique the investigators will find the following, 1. The growth-restricted fetus will have less visceral, subcutaneous, and brown adipose tissue volume and PDFF when compared to healthy fetuses and fetuses whose mothers have gestational diabetes. 2. Fetuses whose mothers have gestational diabetes will have a greater subcutaneous and visceral adipose tissue volume and PDFF compared to healthy fetuses. Specific Aim 2: In a prospective study in pregnant women and their fetuses, the investigators will compare volume and PDFF measurements of fetal visceral, subcutaneous, and brown adipose tissue obtained with FB-MRI to birth growth parameters of these infants. Hypothesis 2: The volume and PDFF of fetal visceral and subcutaneous adipose tissue will correlate positively with birth weight and length z-score.