Fetal pancreatic function in infants of diabetic and rhesus-isoimmunized women

Objective: To measure insulin and glucagon concentrations in amniotic fluid (AF) collected near term in basal conditions and after an arginine test in diabetic, rhesus-isoimmunized, and control pregnant women. Methods: At baseline, AF was collected from 44 diabetic, 32 rhesus-isoimmun ized, and 27 control pregnant women in late pregnancy. Fifty-two diabetic, six rhesus-isoimmunized, and nine control pregnant women had amniocentesis 2 hours after arginine infusion (30 g intravenous/30 minutes) at 33-36 week s. Results: Baseline AF glucose concentrations were significantly greater in d iabetic women than the other conditions, and they related to the gestationa l age in the women with hemolytic disease of the newborn. Insulin and gluca gon AF content of isoimmunized pregnancies overlapped controls, whereas ins ulin and insulin/glucagon molar ratios were significantly higher, and gluca gon values lower, in diabetic pregnancies compared with isoimmunized and co ntrol pregnancies. In isoimmunized pregnancies, the AF concentrations of gl ucose, insulin, and glucagon were correlated with gestational age (less tha n 34, 34 weeks or more). The samples collected after arginine infusion, com pared with those collected at baseline, showed significantly greater insuli n and insulin/glucagon molar ratio values in diabetic (28 +/- 5 versus 11 /- 1 mu U/mL, P = .001; 29.4 +/- 1.7 versus 12.0 +/- 2.8, P = .001) and in Rh pregnant women (18 +/- 6 versus 7.7 +/- 0.7 mu U/mL, P = .001; 30 +/- 9 versus 3.4 +/- 0.4 I/G, P = .001), whereas no significant difference was ob served in the controls. Conclusion: Basal islet hormone concentrations in AF axe modified by matern al diabetes and further influenced by arginine administration. Arginine pro duces an AF response that is similar in pregnancies complicated by diabetes mellitus and rhesus-isoimmunization, despite different (hyperglycemia and euglycemia) maternal blood glucose levels. (C) 2000 by The American College of Obstetricians and Gynecologists.