Normal fetal growth is a critical component for a healthy pregnancy and for ensuring the health and well-being of infants throughout childhood and adolescence. One promising area of research suggests that changes in fetal soft tissue may be the earliest changes that occur in pathologic growth. Three-dimensional volume assessments may be used to detect changes in fetal lean mass, fat mass, and organ size that result from pathologic growth earlier than conventional 2D measures. This knowledge may lead to interventions that could minimize or prevent pregnancy and newborn health problems in the future.

The NICHD Fetal Growth Study was a multi-site, prospective cohort study designed to establish a standard for normal fetal growth (velocity) and size for gestational age in the U.S. population. For the singleton study, 2,334 low-risk, non-obese gravidas were recruited from each of 4 self-identified race/ethnicity backgrounds. An additional 468 obese women and 171 dichorionic twin gestations were recruited. After an initial sonogram in the first trimester, women were randomized to serial ultrasonology schedules. Each schedule comprised five additional sonograms for fetal biometry (six in twins) plus additional image and 3D volume acquisition for later analysis.

Ultrasound measurements at each follow-up visit included standard fetal biometrics ((BPD, HC, AC, FL) and the following volumes in the singleton study if they were able to be obtained: 1st trimester: fetus and gestational sac; 2nd and 3rd trimesters: head, cerebellum, face, chest, heart, abdomen, pelvis, arm and thigh. In twins, the volumes collected were 1st trimester: fetus and gestational sac and in the 2nd and 3rd trimesters the thigh. In addition to ultrasound, this study recorded maternal anthropometrics and a brief interview to capture changes in health status, stress and depression, and physical activity at each follow-up visit. Blood draws at baseline and at targeted gestational ages were obtained for the eventual identification of biomarkers indicative of fetal growth were collected. After delivery, neonatal anthropometric measures were assessed, placental biospecimens were collected, and select information about the obstetrical course and newborn status were abstracted from medical charts.

The Fetal 3D Study is being conducted to catalog and perform 2 Dimensional (2D) and 3 Dimensional (3D) measurement of the obstetrical ultrasound images in the existing bank of singleton and twin gestations collected from the NICHD Fetal Growth Studies. The research study aims to understand the relationship between gravid diseases and longitudinal changes in fetal body composition (subcutaneous fat, lean mass) and organ measurements (in singletons) over the course of pregnancy.

Inclusion Criteria:

• Women with ultrasound data collected from the NICHD Fetal Growth Studies-Singletons and Twin Gestations

Exclusion Criteria:

• None

Participants from the NICHD Fetal Growth Studies-Singletons and Twin Gestations

This project will generate de-identified data derived from human subjects along with various types of analysis to identify unique points of interest and relationships to relevant associated data such as phenotype and/or social states. All information necessary to interpret the data, such as study protocols, data collection instruments, or survey tools will be clearly documented. Data generated by this project will be shared through the NICHD Data and Specimen Hub (DASH), an NIH-funded/-approved public repository.

Data will be shared at the time of publication or shortly thereafter.

Any use of this data by a secondary party after submission to the designated repositories must be shared by that party according to the permissions granted by the original consent form of the study participants unless additional permissions are obtained. Secondary parties must adhere to the NIH Human Data Sharing guidelines for broad data sharing and to the limitations for use set forth by the Institutional Certification associated with this project.