Spiral artery lesions in relation to metabolic control in diabetes mellitus

Decidual and intramyometrial spiral arteries from 18 insulin-dependent diabetic and 18 non-diabetic women were compared histologically. All women were normotensive and none had signs of pre-eclampsia. None of the infants in either group had intra-uterine growth retardation. Metabolic control in the diabetic women was assessed by pregnancy glucose level from the last trimester of pregnancy and by C-peptide in amniotic fluid and cord blood as a measure of the fetal beta-cell function. The intramyometrial and decidual parts of the spiral artery were normal in the non-diabetic group. None of the diabetic patients showed pathological changes in the intramyometrial part of the spiral artery. Two of the 18 diabetic patients had pathological changes (intramural fibrosis) in the decidual portion of the spiral artery. These two women had signs of diabetic angiopathy (White's class D and F) and in one of them, the background diabetic retinopathy progressed markedly during pregnancy. The pregnancy glucose level was above normal (greater than 6.2 mM/l) in 3 of 18 diabetics. The C-peptide values in amniotic fluid and cord blood were above normal in 11 of 17 and in 5 of 17, respectively. Both patients with spiral artery lesions had pregnancy glucose levels in the upper range, 5.86 and 5.98 mM/l, respectively and the highest value of C-peptide in the amniotic fluid and cord blood, suggesting exaggerated fetal beta-cell function.