Assessment of fetal cardiac function using the modified myocardial performance index in third-trimester fetuses of diabetic mothers

Objective To determine whether the fetal cardiac function is impaired in fetuses of diabetic mothers in the third trimester using the Doppler-based modified myocardial performance index (Mod-MPI) compared with gestational age-matched controls. Study design A cross-sectional observational study. Patients and methods The study included 45 diabetic pregnant women in the third trimester and 52 gestational age-matched controls. Measurement of glycosylated hemoglobin level (HbA1c) was performed to validate the quality of metabolic control. Selected patients underwent a fetal echocardiographic examination to determine the Mod-MPI. The isovolumetric contraction time (ICT) was measured from the closure of the mitral valve to the opening of the aortic valve (AV), the ejection time (ET) from the opening to the closure of the AV, and the isovolumetric relaxation time (IRT) from the closure of the AV to the opening of the mitral valve. The Mod-MPI was calculated as (ICT+IRT)/ET. Results A total of 28 patients in the diabetic group had well-controlled diabetes, whereas the remaining 17 patients with a serum HbA1c more than 7% had poorly controlled diabetes. The IRT was significantly shorter in the control group than both the well-controlled diabetics (P<0.01) and the poorly controlled diabetics (P<0.001). The overall Mod-MPI was statistically significantly lower in the control group than the study group as a whole (P<0.001) as well as in the poorly controlled diabetics (P<0.001), but although it was lower than in the well-controlled diabetics, the difference did not reach statistical significance (P=0.053). Conclusion Fetuses of diabetic mothers show evidence of third trimesteric diastolic myocardial dysfunction as shown by a higher Mod-MPI than age-matched controls that appears more marked in fetuses of mothers with poorly controlled diabetes.