Correlation between fetal subcutaneous fat thickness and insulin resistance through cord blood analysis immediately after delivery

This study aimed to determine whether fetal subcutaneous tissue (SCT) thickness, measured using ultrasound immediately before and after delivery, can reflect changes in glucose metabolism immediately after delivery. We also evaluated the impact of insulin resistance changes during pregnancy by comparing pregnant women with well-controlled gestational diabetes mellitus (GDM) and those with normal glucose metabolism. The study participants were 117 pregnant women, including 97 controls and 20 patients with GDM who visited our obstetric clinic between February and December 2022. The participants were scheduled for cesarean delivery at a gestational age of ≥37 weeks. SCT thickness before delivery was measured using ultrasound and within 48 h after delivery using Holtain calipers. The glucose and insulin concentrations were quantified from cord blood collected immediately after delivery. Based on these results, a Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) was performed to assess insulin resistance. Independent t -test or Wilcoxon rank-sum test for continuous variables and Fisher’s exact test for categorical variables were used to compare the various parameters. Correlations among the variables in each group were assessed by calculating the correlation coefficient (Pearson’s correlation). SCT thickness measured using ultrasound and calipers demonstrated a strong correlation where pregnant women with GDM exhibited thicker fetal SCT and neonate skinfolds than in those without GDM. Glucose and insulin levels in the cord blood were significantly elevated (p < 0.05) in the gestational diabetic group, along with remarkable differences (p < 0.001) in HOMA-IR. These variables indicated a higher prevalence of glucose intolerance in the neonates of mothers with GDM. In pregnant women with GDM, there was a statistically significant correlation between fetal abdominal SCT thickness and glucose levels (r = 0.64, p < 0.01) and HOMA-IR (r = 0.48, p < 0.05). Measuring the subcutaneous fat thickness of the fetus shortly before delivery is beneficial for predicting insulin resistance in neonates. This is considered particularly useful for women with effectively managed GDM, where the presence of conditions such as macrosomia may not be pronounced.