2025 Scholars' Research Symposium Abstract: Ultrasonographic Accuracy in Rural vs Urban Counties.

Abstract

Introduction: Rural women experience substantial, multifactorial health disparities including lower socioeconomic status, insurance access, and geographic barriers. South Dakota has the second largest proportion of maternity care deserts (56.1%) and births to parents residing in these areas (23.2%) in the United States. These factors delay prenatal care initiation and increase infant mortality. Reliable prenatal ultrasonography for rural Americans is critical for birth planning and referral to higher care facilities. The objective of this study was to determine whether ultrasonography performed in rural counties, in the second trimester, is as accurate for newborn weight prediction and detection rate for congenital abnormalities compared to ultrasonography performed in urban counties.

Methods: Retrospective, longitudinal chart review study approved by the Sanford Health Institutional Review Board correlating the second trimester prenatal screening examination with postnatal outcomes. Accuracy of newborn weight prediction for term pregnancies and congenital anomalies was compared between rural and urban clinics for mother-newborn dyads across the Sanford Health blueprint. Patients were classified as rural if they received their second trimester ultrasound at a facility in a county with a population of less than 50,000. Groups were compared via two sample t-test, Analysis of Variance, and linear regression to identify relationships and potential confounders as appropriate using Graphpad Prism software version 10 with p-values less than 0.05 considered significant.

Results: A total of 278 mother-newborn dyads (n = 70 rural and n = 208 urban) were included in the study. Nonsingleton infants, pregnant individuals less than 18 years old, and patients whose second trimester ultrasound was unobtainable were excluded. Fetal weight percentile was not determined to be predictive of birth weight percentile in rural (R-squared = 0.165) or urban (R-squared = 0.1103) communities, nor were the differences between the linear regression models statistically significant (p = 0.7478). Detection rate of birth abnormalities for neuro, craniofacial, cardiac, gastrointestinal, renal/genitourinary, and limbs was recorded. The overall percentage of anomalies identified at the second trimester ultrasound was 50.0% for rural and 31.7% for urban, which was not determined to be statistically significant (p = 0.6416).

Conclusion: This study showed no statistically significant differences between ultrasonography performed in rural vs urban counties, in the second trimester, regarding the accuracy for newborn weight prediction or detection rate of congenital anomalies within our single health system. To the author's knowledge, this is the first study to investigate disparities in ultrasonography accuracy across U.S. rural and urban communities. Enhanced understanding of how potential sources of error, including patient volume, specialized expertise of the ultrasonographer, and equipment, is needed to improve prenatal assessment reliability for informed decision-making and ultimately maternofetal outcomes in rural communities. Future work should seek to expand the sample sizes to further stratify the population groups and control for ultrasound equipment, ultrasonographer, and who read the scans.