Prediction of Fetal Hypertrophic Cardiomyopathy in Diabetic Pregnancies Compared with Postnatal Outcome.

OBJECTIVE: The aim of this study was to estimate the accuracy of prenatal assessment of interventricular septum (IVS) thickness, right myocardial wall thickness (RMWT), and left myocardial wall thickness (LMWT) by two-dimensional (2D) ultrasound for the prediction of perinatal mortality and postnatal diagnosis of hypertrophic cardiomyopathy (HCM) among diabetic pregnant women.

SUBJECTS AND METHODS: A total of 120 diabetic pregnant women at 35 weeks or more were enrolled in this study from January 1, 2012, to June 30, 2014, at Ain Shams Maternity Hospital, Cairo, Egypt. The 2D ultrasound was done once for all the participants at the time of recruitment; IVS thickness, RMWT, and LMWT were measured. The glycosylated hemoglobin (HbA1c) levels of the participants were recorded. Neonatal assessment including postnatal echocardiography was done after 48 hours. Postnatal results were compared with the prenatal predictive results.

RESULTS: Higher thickness values for IVS, RMW, and LMW were obtained in the uncontrolled diabetic cases (HbA1c > 6.5%) than in the controlled diabetic cases (HbA1c < 6.5%; P < 0.01). Of the included 120 neonates, 10 (8.3%) were stillborn, 99 (82.5%) had a five-minute Apgar score ≥7, and 4 (3.3%) had a five-minute Apgar score ≤3. The four neonates with severe neonatal distress died after admission to neonatal intensive care unit within one week after delivery. Out of 110 live-born neonates, 4 (3.6%) neonates had a low ejection fraction (EF) (<50%) due to HCM; of them 2 (1.8%) died within one week after delivery, while 2 (1.8%) survived. Another two (1.8%) neonates died from severe respiratory distress syndrome. A cutoff value of ≥4.5 mm for prenatal IVS thickness was predictive of neonatal distress due to HCM with a sensitivity of 82%, specificity of 68%, and diagnostic accuracy of 72%. A cutoff value of <1.18 for the ratio of IVS thickness to LMWT had a sensitivity of 82%, specificity of 72%, and diagnostic accuracy of 74% for the prediction of neonatal distress due to HCM. In this study, 8 of the 10 fetuses with intrauterine demise and the 2 neonates who died within one week after delivery due to heart failure had a prenatal IVS thickness of ≥4.5 mm, while 7 of the 10 fetuses with intrauterine demise and the 2 neonates who died postnatal from heart failure had a prenatal IVS thickness to LMWT ratio of ≤1.18.

CONCLUSION: A prenatal IVS thickness of ≥4.5 mm or an IVS/LMWT ratio of ≤1.18 seems to be predictive of HCM and is associated with almost twofold higher risk of intrauterine fetal death and almost threefold higher risk of possibly relevant perinatal mortality.