Amer J Perinatol
DOI: 10.1055/s-0037-1608926
Original Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Characterization of Thermal and Mechanical Indices from Serial Ultrasound Exams and Associations with Neonatal Anthropometry: The NICHD Fetal Growth Studies

Melissa M. Smarr1, Germaine M. Buck Louis1, Paul S. Albert2, Sungduk Kim2, Karin M. Fuchs3, Jagteshwar Grewal1, Mary E. D'Alton3, Katherine L. Grantz4
  • 1Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland
  • 2Division of Cancer Epidemiology and Genetics, Department of Biostatistics, National Cancer Institute, Bethesda, Maryland
  • 3Department of Obstetrics and Gynecology, Columbia University Medical Center, New York, New York
  • 4Division of Intramural Population Health Research, Department of Epidemiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland
Further Information

Publication History

11 August 2017

31 October 2017

Publication Date:
30 November 2017 (eFirst)


Objective This article aims to determine if the number of maternal ultrasound scans where the highest thermal (TI) or mechanical (MI) indices recorded during obstetrical ultrasound exceed 1.0 were associated with neonatal anthropometric measurements.

Study Design A prospective cohort of 2,334 nonobese low-risk pregnant women from 12 U.S. clinical sites underwent a total of six ultrasound scans, for which the highest TI and MI values were recorded. Neonatal anthropometric measurements were obtained within 12 to 24 hours of delivery. Multiple linear regression models adjusted for maternal race/ethnicity, body mass index, weight gain, and gestational age were used to examine associations between the number of maternal ultrasounds during gestation with a TI or MI exceeding 1.0 and the mean change in neonatal anthropometry.

Results Ultrasounds with TI or MI >1.0 were not associated with birth weight, neonatal length, nor head, chest, and abdominal circumferences. TI >1.0 was negatively associated with neonatal mid-upper arm and mid-upper thigh circumferences. MI >1.0 was negatively associated with neonatal skinfold measurements of the anterior thigh and triceps, and neonatal circumferences of the mid-upper thigh and umbilicus.

Conclusion Prenatal ultrasound examinations in which TI or MI intermittently exceeded 1.0 did not identify a pattern of alterations of birth size.