ABSTRACT
To look for any increase in proinsulin or proinsulin/insulin ratio in women suffering GDM as an additional factor to their insulin resistance state during pregnancy; and to test for its reversibility in the post partum period. The study was conducted on 30 pregnant age matched women in their second or third trimester and 10 age matched non pregnant normoglycemic women as a reference group. The pregnant women were divided into 3 groups each of ten as follow: normoglycemic women with normal OGTT as a control group, obese women with GDM and lean women with GDM. All women were subjected to full history taking and complete clinical examination. The following parameters were measured: diagnostic OGTT using 100 gm glucose, fasting serum proinsulin, fasting serum insulin, serum C-peptide, proinsulin/insulin ratio and insulin sensitivity. All these tests were repeated 4-8 weeks postpartum. The results of the study revealed that the serum levels of proinsulin and the proinsulin/insulin ratio were significantly higher in obese and lean women with GDM than the control and reference groups during pregnancy and also after delivery. The insulin sensitivity index was significantly lower and the relative resistance for insulin was significantly higher in GDM women compared with normal glucose tolerant pregnant women during pregnancy, while after delivery the sensitivity index was significantly higher than during pregnancy in GDM women as well as pregnant women with normal OGTT. The mean values of C-peptide were significantly higher in GDM patients versus control and reference groups during pregnancy. After delivery these mean values of C-peptide were significantly lower than during pregnancy in the three pregnant studied groups. Women with GOM are characterized by elevated serum proinsulin concentrations and increased proinsulin/insulin ratio which reflect beta-cell decompensation. These precursors molecules might thus serve as a marker for the disease and potentially even identify the subjects of high risk for development of type 2 diabetes. Also, it may be possible to detect such beta-cell stress earlier in pregnancy and to use this phenomena in the assistance of better prediction of GDM