Association between maternal body mass index and increased fetal pancreatic circumference in normoglycemic pregnancies: a prospective cross-sectional study

OBJECTIVE: To evaluate the association between maternal body mass index (BMI) and fetal pancreatic circumference (PC) in singleton pregnancies without gestational diabetes mellitus (GDM), and to determine whether maternal obesity is related to pancreatic changes independent of conventional fetal growth parameters. METHODS: This prospective multicenter cross-sectional study included normoglycemic singleton pregnancies assessed in the second (n = 142) and third (n = 154) trimesters. All participants underwent a 75-g oral glucose tolerance test (OGTT), and GDM cases were excluded. Maternal BMI was categorized according to World Health Organization (WHO) criteria. Fetal PC was measured using a standardized freehand tracing technique, and the mean of three measurements was recorded. Comparisons among BMI groups were performed using ANOVA and ANCOVA adjusted for fetal abdominal circumference (AC). Correlation and multivariable logistic regression analyses were conducted to assess associations with composite adverse neonatal outcomes (CANO). RESULTS: Maternal, fetal, and neonatal characteristics, including estimated fetal weight, AC percentile, birth weight, and Apgar scores, were similar across maternal BMI categories. However, fetal PC differed significantly by maternal BMI in both trimesters. In the second trimester, mean PC was 6.44 ± 0.86 cm in normal-weight women, 7.10 ± 0.94 cm in overweight women, and 7.11 ± 0.98 cm in obese women (p = 0.008), remaining significant after AC adjustment (p = 0.021). In the third trimester, PC increased progressively (6.84 ± 0.48 cm, 7.64 ± 0.78 cm, and 7.93 ± 1.04 cm; p = 0.004), persisting after adjustment (p = 0.003). PC correlated positively with maternal BMI, gestational age, and AC. Neither BMI nor PC independently predicted adverse neonatal outcomes. CONCLUSION: Higher maternal BMI is associated with increased fetal PC independent of conventional growth parameters, suggesting organ-specific intrauterine effects even without GDM. Short-term neonatal outcomes were unaffected.