PED NEONAT 20-000599 Fetal Body Composition

Obesity is an ongoing public health problem that is difficult to treat. There is evidence that obesity has fetal origins. Body composition, including visceral, subcutaneous, brown, and hepatic fat have been found to be important predictors in obesity and metabolic syndrome. Magnetic resonance imaging (MRI) can quantify body composition that does not require radiation but is motion limited. The investigators have developed a motion-compensated MRI sequence, also known as "free breathing" MRI. In this study, the investigators plan to obtain free-breathing MRIs of pregnant women in the third trimester of pregnancy. MRIs will be obtained from healthy mothers, mothers with growth-restricted fetuses, and mothers with gestational diabetes. The different types of adipose tissue will be measured and compared between groups and correlated to birth growth parameters. The goal is this study is to assess if motion-compensated MRI can help predict early growth patterns in infancy.

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.

Eligibility Criteria:
Inclusion Criteria:

* Pregnant women with singleton pregnancies (healthy cohort)
* Pregnant women with fetuses with weights \< 10th percentile weight for gestational age (IUGR cohort)
* Pregnant women with gestational diabetes (diabetes cohort)

Exclusion Criteria:

* Pregnant minors
* Major congenital anomalies or disease processes in the fetus
* Fetus with known chromosomal anomalies
* Mothers who do not plan to deliver at UCLA
* Multiple pregnancy (i.e. twins, triplets, etc)
* History of claustrophobia
* Contraindications to MRI such as metallic devices in the body that are not MRI compatible