Umbilical blood gases, fetal glycemia and fetal-placental haemodynamics in pregnancies complicated by insulin-dependent diabetes mellitus

Abstract

Objective: Fetal acidaemia and hypoxemia may be the result of placental insufficiency as well as the metabolic effect of maternal diabetes mellitus.

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Methods: Fetal blood (FB) was sampled from the umbilical vein by transabdominal cordocentesis in 24 women with pregnancy, complicated by insulin-dependent diabetes (IDD) and 22 normal pregnancies at 33-37 weeks gestation, which was performed immediately after Doppler examination. Blood velocity systolic-diastolic (S/D) ratio was calculated in fetal descending aorta, umbilical and middle cerebral arteries, and also cerebro-placental ratio. Blood gases were determined using blood gas analyzer “ABL-30” “Radiometer”. Fetal blood samples were assayed for glucose levels by standard glucose-oxidase-perocxidase method. The statistics was made using Student t-test and correlation analysis.

Results: Some fetuses (n=7) in diabetic pregnancies were acidaemic, but in the absence of acidosis in the most of them umbilical venous hypoxemia (n=18) and hypercapnia (n=16) were present. The mean S/D ratio in umbilical artery, fetal descending aorta in diabetic pregnancies were statistically significantly higher than in normal pregnancies and cerebro-placental ratio — lower. Associations between S/D ratio in umbilical artery, cerebro-placental ratio and umbilical venous pH (r=-0,596, p<0,01 and r=0,404, p<0,05, respectively), pCO2 (r=0,613, p<0,01 and r=- 0,506, p<0,05, respectively) were found. Fetal blood glucose concentrations in pregnancies, complicated by IDD were significantly associated with umbilical venous pH (r=-0,616, p<0,01), pO2 (r=-0,469, p<0,05) and pCO2 (r=0,404, p<0,05).

Conclusions: In pregnancies, complicated by IDD fetal-placental haemodynamic changes (increase of peripheral placental resistance and centralization offetal circulation) and fetal hyperclycaemia have been associated with fetal acid base disturbance.