The purpose of the study is to show if it's possible to use a special kind of ultrasound called backscatter quantitative ultrasound (bQUS) to check on a baby's lungs when the mother is 36 weeks pregnant. 16 participants will be on study for a single 30 minute ultrasound between 32 and 36 weeks of pregnancy.

Primary Objective:

• Demonstrate the feasibility of performing bQUS analysis on ultrasound echo signals acquired of the fetal lung acquired with clinical ultrasound scanners during third -trimester ultrasound scans

Secondary Objectives:

• Design and implement a protocol to acquire non-processed (raw) echo signals from a commercial ultrasound scanner necessary to perform bQUS at the UPH-Meriter Center for Perinatal Care (CPC).
• Quantify the populational variance of quantitative features extracted from bQUS applied to ultrasound data collected from third trimester ultrasound scans of the fetal lung.

The study will be divided into two phases: (i) feasibility phase and (2) hypothesis-testing phase recruitment phase. Phase 1 will provide evidence of the technical viability of data acquisition at UPH-Meriter CPC and will involve 5 participants. Technical challenges will be discussed with the research team and the supporting vendor (GE) to decide whether the technique is viable to move forward. In case the decision is favorable, recruitment will continue to complete 16 participants to estimate the populational variance of the quantitative features. If the decision is not favorable due to technical complications, the study will be terminated.

Inclusion Criteria:

• Pregnant females ages 18 to 45 years old with singleton pregnancy, live fetus, gestational age between 32.1 and 36.7 weeks, not in labor, scheduled for routine ultrasound growth evaluation.
• Gestational age determined by the date of the last menses, and confirmed by measurement of the crown-rump-length on transabdominal ultrasound.

Exclusion Criteria:

• Subjects unable to consent
• Active Labor
• Fetal malformations of the lungs
• Prescription of corticosteroids prior to ultrasound evaluation
• Pre-gestation or gestational diabetes mellitus
• Low English proficiency, needing an interpreter

Pregnant females ages 18 to 45 years old with singleton pregnancy, live fetus, gestational age between 32.1 and 36.7 weeks, not in labor, scheduled for routine ultrasound growth evaluation

Data sharing with external collaborators will be provided through FlyWheel Exchange.

Coded data and the linking files will be stored for 7 years after conclusion of the study. After seven years, linking files and codes will be destroyed, and the de-identified data will be stored indefinitely for potential future research use.

Permission to access data will be provided within Data Sharing Agreements and only after IRB approval.