[Blood sugar and plasma immunoreactive insulin levels in healthy pregnant women undergoing the glucose tolerance test]

Abstract

The level of blood sugar and of blood plasma immunoreactive insulin (IRI) on fasting stomach and during the glucose (per os) tolerance test (GTT) were studied in apparently healthy 8 nonpregnant and 20 pregnant women (11 of them were examined once and 9 repeatedly in the course of pregnancy). GTT proved to be normal in all the women; there sere no signs pointing to the possibility of prediabetic state. Blood sugar on fasting stomach was somewhat lower in pregnant women than in the nonpregnant ones. Therefore, despite the absence of significant differences between the mean blood sugar values during the GTT in the pregnant and onopregnant women the mean sugar elevation during the whole GTT period was significantly higher in women of the III trimester of pregnancy than in the nonpregnant women. Blood plasma IRI content on fasting stomach during the II trimester of pregnancy had a tendency to elevation, and during the III trimester was significantly greater than in the nonpregnant women and in the I and II trimesters of pregnancy. The maximal blood plasma IRI elevation after taking glucose occurred later in the pregnant women was significantly higher during the II and the III trimesters than in the nonpregnant women. During the III trimester of pregnancy there was a singnificantly greater mean IRI elevation in the whole course of the GGT than in the nonpregnant women. IRI index showed no significant change in the pregnant women. The revealed character of the sugar and IRI ratio in the blood on fasting stomach and during the GTTpermits to suggest that hyperinsulinemia during pregnancy bore the character of a compensatory process. The absence of any changes in the IRI index pointed to the functional preservation of the insular apparatus in healthy pregnant women despite the fact that it was subject to a constant and increasing tension with the progress of pregnancy.