Blood viscosity in umbilical cord blood from babies of diabetic mothers

Placental and fetal Doppler velocimetry in pregnancies complicated by maternal diabetes mellitus

OBJECTIVE

Our purpose was to investigate placental and fetal circulation in pregnancies complicated by maternal diabetes mellitus and to relate any changes to fetal blood pH, Po2, and hematocrit.

STUDY DESIGN

Doppler measurements of both uterine arteries, one umbilical artery, the fetal descending thoracic aorta, and one fetal middle cerebral artery were performed in 65 well-controlled diabetic pregnancies in a cross-sectional study at the Harris Birthright Research Centre for Fetal Medicine, London. In 41 cases cordocentesis was also performed for the measurement of umbilical venous blood pH, Po2, and hematocrit.

RESULTS

The mean umbilical venous blood pH was significantly lower and the hematocrit significantly higher than the appropriate normal mean for gestation. However, the Doppler indices of the placental and fetal circulations were essentially normal, except in some of the cases complicated by preeclampsia or intrauterine growth retardation.

CONCLUSIONS

Maternal diabetes mellitus is not associated with abnormalities in Doppler indexes of the placental or fetal circulations.

Fetal polycythemia and thrombocytopenia in pregnancies complicated by maternal diabetes mellitus

In 40 pregnancies complicated by maternal diabetes mellitus umbilical venous blood was obtained by cordocentesis within 24 hours of elective delivery at 36 to 40 weeks' gestation. The mean fetal hematocrit was significantly higher and the mean platelet count significantly lower than the corresponding values of our reference ranges. Furthermore, blood gas analysis demonstrated these fetuses to be normoxemic but acidemic. The degree of fetal acidemia was significantly associated with both maternal and fetal blood glucose concentrations. The fetal hematologic indices were significantly related to the maternal glycosylated hemoglobin percentage but not to the degree of fetal acidemia or to the maternal or fetal blood glucose concentration at the time of cordocentesis. Fetal acidemia, polycythemia, and thrombocytopenia may contribute to the increased incidence of late unexplained intrauterine deaths in pregnancies complicated by maternal diabetes mellitus.

Correlation of umbilical cord whole blood viscosity and the presence of fetal distress at birth: a mathematical modelling study

This study was designed to investigate the relationship between umbilical cord blood viscosity and clinical parameters such as maternal parity, maternal smoking, mode of delivery, sex of infant and the incidence of fetal distress at birth using mathematical modelling. The results demonstrated vaginal delivery, male infants, infants of primigravidas and low cord whole blood viscosity at a high shear rate were covariables and were associated with an increased incidence of fetal distress and low Apgar scores.

Correlation between umbilical vein blood flow and umbilical blood viscosity in normal and complicated pregnancies

Umbilical vein blood flow (UVBF) was studied during the last 24 h before delivery using a combination of real-time and Doppler ultrasonic equipment in 64 normal and pathological pregnancies and the results were correlated with the values of whole blood viscosity taken from the umbilical vein after delivery. UVBF was reduced in the subgroup with chronic fetal distress (n = 14) (P less than 0.001) and the hypertensive pregnancies (n = 17) (P less than 0.05), whereas umbilical blood viscosity was increased only in the subgroup with chronic fetal distress (P less than 0.01) as compared with the normal pregnancies (n = 24). A significant positive correlation was observed between the umbilical blood viscosity and haematocrit values in all the groups of patients. UVBF and blood viscosity had a significant negative correlation in chronic fetal distress (P less than 0.001) and in hypertensive pregnancies (P less than 0.05), but not in normal or diabetic pregnancies (n = 9). Thus haemoconcentration leading to increased fetal blood viscosity may act as an aetiological factor in the reduction of UVBF in developing fetal distress.