Cardiac compliance in fetuses of diabetic women

Abstract

Objective: To examine possible changes in cardiac function in fetuses of pregestational diabetic mothers. Methods: We conducted a prospective longitudinal study of 31 women whose pregnancies were between 22 weeks’ gestation and term, and who had pregestational diabetes. All diabetic women included in the study had glycosylated hemoglobin lower than 6.5%. All patients included in the study had an early ultrasound confirming gestational age. Doppler studies of the blood flow through the mitral and tricuspid valves were done every 4 weeks using a pulsed-wave Doppler ultrasound device with a 3.5- or 5-MHz transducer. The following indices were calculated from the flow velocity waveforms: the peak velocity during the rapid ventricular filling (E wave) and during the atrial systole (A wave), and the ratio between these velocities (E/A ratio); and the velocity time integral of the atrioventricular blood flow (this integral correlates with volume flow). A comparison between the Doppler indices obtained in fetuses of diabetic women and of normal women was made by using the Mann-Whitney test. Results: Each patient had four to five fetal echocardiographic examinations at 22, 26, 30, 34, and 38 weeks’ gestation. The E/A ratio of the mitral and tricuspid valves did not increase in fetuses of diabetic women during the third trimester and was significantly higher in fetuses of nondiabetic women compared with fetuses of diabetic women at 34 and 38 weeks’ gestation. The velocity time integral of the mitral and tricuspid valves multiplied by heart rate was higher, but not significantly, in fetuses of nondiabetic women compared with fetuses of diabetic women at 34 and 38 weeks’ gestation. The E-wave of the mitral and tricuspid valves increased in both groups throughout gestation. The A-wave of the mitral and tricuspid valves increased only in fetuses of diabetic women throughout the third trimester and was significantly higher at 34 and 38 weeks’ gestation compared with fetuses of nondiabetic women. Conclusion: Differences in atrioventricular blood flow patterns between fetuses of diabetic women and normal fetuses do not necessarily result from differences in cardiac compliance.