Assessment of Beta-Cell Function During Pregnancy and after Delivery

The aim of the present study was to assess β-cell function using homeostasis model (HOMA-B) and disposition index (DI) in pregnant women with/without gestational diabetes, and after delivery. A total of 102 pregnant women between 24-28 gestational weeks (53 with gestational diabetes mellitus (GDM) and 49 with normal glucose tolerance (NGT) and 22 GDM postpartum women (8-12 weeks after delivery) were included in the study. All postpartum women had a history of GDM. HOMA indexes (insulin resistance - HOMA-IR and HOMA-B for assessing β-cell function) were calculated from fasting glucose and insulin concentrations. To estimate insulin secretion independent of insulin sensitivity, DI was calculated using glucose and insulin levels at 0 and 60 min during the course of a 2 h 75g oral glucose tolerance test (OGTT). In GDM pregnant women HOMA-B was significantly lower compared to NGT women (p = 0.017), but there was no significant difference compared to women after birth (NS). There was difference between NGT and postpartum women (p < 0.05). DI was significantly lower for GDM pregnant women in comparison to NGT and postpartum women (p < 0.0001; p = 0.011), between NGT and women after birth (p < 0.04). In our study, comparison of НОМА-В in NGT and GDM pregnant women demonstrated that the OR of developing GDM was 0.989 (95% CI, 0.980-0.998, P = 0.013), and comparison of DI in healthy pregnant and GDM showed that the OR of developing GDM was 0.967 (95% CI, 0.947-0.988, P = 0.002). Therefore, HOMA-B and DI appear to be protective factors in the risk of developing GDM. According to our results, assessment of β-cell function, using HOMA-B and DI, showed that they are lower in GDM than NGT group and postpartum women. It is important to note that HOMA-B did not show significant difference between GDM pregnant and women after delivery with a history for GDM. We assume that pregnant women with GDM have a pancreatic β-cell defect that remains after birth. These women are at increased risk for developing diabetes mellitus, the most frequent type 2 diabetes, in the future after birth.