Prenatal ultrasound study on the effect of gestational diabetes mellitus on fetal pancreatic development

Abstract Objective To evaluate the impact of gestational diabetes mellitus (GDM) on fetal pancreatic development using prenatal ultrasound, and to delineate the gestational age (GA)-specific patterns of pancreatic growth in GDM fetuses. Methods This study enrolled 408 normoglycemic controls and 132 GDM fetuses. Fetal pancreatic circumference (PC), pancreatic area (PA), and abdominal circumference (AC) were measured at 15–39 weeks, with the AC/PC ratio calculated. Reference equations for PC and PA against GA were built on controls. Multiple linear regression assessed the independent correlation between GDM and pancreatic measurements, and ANCOVA compared fetal parameters across GA subgroups of the two groups. Results Reference models of PC and PA exhibited excellent fit ( R 2 = 0.9778 and 0.9441, respectively). After confounder adjustment, GDM independently predicted increased PC and PA (both P < 0.001), with significant GDM-by-GA interactions for PC, PA, and AC (all P < 0.01). Pancreatic enlargement was evident at 20–31 weeks, maximal at 28–31 weeks; no significant differences at 15–19 or 32–39 weeks. Conversely AC showed a biphasic pattern, increasing at 20–23 weeks but decreasing at 32–39 weeks, with no differences at other gestational windows. The AC/PC ratio in the GDM group was lower than controls from 20 weeks onward (all P < 0.05), with the largest gap at 24–27 weeks. Conclusion Pancreatic enlargement in GDM fetuses occurs earlier than the clinical diagnostic window and exhibits a distinct temporal dissociation from truncal growth, suggesting a more sustained and less reversible morphological alteration.