Abstract

Objective: To evaluate if maternal glucose level and growth of the fetus were related to placental vascular impedance in pregnancy complicated by gestational diabetes mellitus.

Material and methods: A retrospective study of 146 gestational diabetic women of which 117 needed insulin therapy. Glycosylated hemoglobin (HbA_1c) was evaluated as well as umbilical and uterine artery Doppler velocimetry. The results were related to adverse outcome of pregnancy including newborn birthweight.

Results: Abnormal umbilical artery blood flow velocity was seen in 5% of the cases and abnormal uterine artery flow in 16%. Uterine and umbilical artery vascular impedance was significantly lower in macrosomic newborns. There was a poor correlation between HbA_1c, vascular impedance and birthweight. There were 11 cases that developed preeclampsia, all having abnormal uterine artery Doppler and two abnormal umbilical artery Doppler.

Conclusion: Uterine and umbilical artery vascular impedance in pregnancies complicated by gestatinal diabetes is related to birthweight and placental weight, but not to maternal HbA_1c levels. Placental Doppler ultrasound does not seem to be of clinical value for fetal surveillance in these pregnancies unless the pregnancy is complicated by preeclampsia and/or intrauterine fetal growth restriction.