Umbilical arterial Doppler sonography for fetal surveillance in pregnancies complicated by pregestational diabetes mellitus.

Antepartum fetal surveillance constitutes an essential component of the standards of care in managing pregnancies complicated by pregestational diabetes mellitus. Fetal hyperglycemia is associated with increased oxidative metabolism, hypoxemia and increased brain and renal perfusion without any significant changes in fetoplacental perfusion. Human cordocentesis data show that fetal hypoxemia and acidemia are associated with changes in the umbilical arterial Doppler indices in maternal diabetes mellitus complicated by fetal growth restriction or pre-eclampsia. Consistent with this, observational studies suggest significant diagnostic efficacy of the Doppler method in diabetic pregnancies complicated by vasculopathy, and in the presence of fetal growth restriction or hypertension. However, the relationship between abnormal umbilical arterial Doppler indices and the quality of glycemic control remains unproved. Although there are no randomized trials specifically addressing this issue, existing evidence suggests that Doppler velocimetry of the umbilical artery may be beneficial for antepartum fetal surveillance in diabetic pregnancies complicated by vasculopathy, fetal growth restriction or hypertension.