Assessment of the Fetal Myocardial Performance Index in Well-Controlled Gestational Diabetics and to Determine Whether It Is Predictive of Adverse Perinatal Outcome

This study was aimed at determining if the myocardial performance index (MPI) is altered in well-controlled gestational diabetics and if so whether it is predictive of adverse perinatal outcome. In a prospective cross-sectional study, 54 consecutive women with well-controlled gestational diabetes controlled on insulin or metformin in the third trimester were recruited and matched with 54 women with normal pregnancies (control group). Using Doppler echocardiography, the MPI was calculated. Sonographic biophysical and placental resistance Doppler markers in both groups were also determined. An abnormal outcome was defined as any of the following: stillbirth; neonatal death; neonatal intensive care admissions; tachypnea with pulmonary edema; neonatal cord pH < 7.15; 5-min Apgar score < 7, polycythemia; and nucleated red blood cells > 10/100 white blood cell counts, hypoglycemia. The MPI was significantly higher in the diabetic group compared to controls (p < 0.0001). Rate of adverse outcome was 22% in the diabetic group. The diabetic group with adverse outcomes had significantly elevated MPI values compared to the diabetic group with normal outcomes. There were 26 diabetics controlled on metformin and 28 controlled on insulin. The adverse outcome rate was slightly higher in the IDDM group compared to the non-insulin-dependent group but was not statistically significant. The main adverse outcomes were low Apgars (18%), hypoglycemia (22%), polycythemia (13%) and low pH in 7%. All control births had normal outcomes. MPI served as an independent predictor of adverse outcome. The MPI z-score had a good diagnostic accuracy as evidenced by the area under the ROC curve of 0.83. An MPI z-score exceeding 4.55 conferred a 90% sensitivity and 74% specificity, with 77% of outcomes correctly classified with a likelihood ratio of 3.5. The MPI is impaired in fetuses in well-controlled gestational diabetes, with fetuses with an adverse outcome having significantly higher MPI values compared to the fetuses with normal outcome in the diabetic group. MPI has the potential to improve fetal surveillance in gestational diabetes.