Neopterin Concentration in Umbilical Cord Blood as a Reflection of Maternal Insulin Resistance—A Pilot Study

Background/Objective: Insulin resistance (IR) during pregnancy, even in women with normal body mass index (BMI), may affect maternal and fetal metabolic and immune status. This study aimed to evaluate neopterin (NPT), leptin, insulin, and ghrelin concentrations in maternal blood (MB) and umbilical cord blood (CB) in normoglycemic women with and without IR, all with normal BMI. Methods: Peripheral and cord blood was collected from 36 Caucasian women with term, uncomplicated vaginal deliveries. The participants were classified into control (n = 16; age = 30.81 ± 4.875 years) and IR (n = 20; age = 31.95 ± 4.979 years) groups based on a professional medical diagnosis. Anthropometric parameters were recorded, and metabolic/hormonal markers were measured using ELISA and RIA. Results: NPT concentrations in CB were significantly higher in the IR group (p < 0.05), correlated positively with MB NPT levels (r = 0.3809, p < 0.05). A significantly higher concentration of both insulin and leptin was observed in the MB of women with IR compared to the control group (p < 0.0001), whereas in CB, only insulin concentration was significantly higher in the IR group than in healthy controls (p < 0.05). Ghrelin levels did not differ between the groups. Conclusions: Insulin resistance in non-obese pregnant women is associated with increased NPT concentration in CB, which may suggest fetal immune activation. However, defining the role of NTP as a metabolic “messenger” between mother and child requires further study.