Increased fetal epicardial fat thickness: A novel ultrasound marker for altered fetal metabolism in diabetic pregnancies

Objective To evaluate whether fetal epicardial fat thickness (EFT) differs in diabetic and nondiabetic pregnant women. Methods Retrospective case‐control study of pregnancies between 24 and 36 weeks complicated by preexisting (PDM) or gestational (GDM) diabetes mellitus, matched one to one with controls for body mass index and gestational age (GA). Epicardial fat was identified as the hypoechogenic area between myocardium and visceral pericardium over the right ventricle and its thickness was measured by a single observer blinded to clinical condition and outcomes. A linear regression analysis was performed to assess the relationship between GA and EFT, and regression lines were compared between diabetics and controls. Results 53 PDM and 53 GDM pregnant women were matched with controls. With the exception of maternal age, the demographics were similar among groups. EFT increased significantly with advancing gestation in both diabetics and controls ( P < 0.0001) and was significantly greater in diabetics than in controls ( P < 0.0001). The best fit lines were different between diabetics (EFT = 0.05 × GA + 0.07 mm; R 2 = 0.70) and controls (EFT = 0.07 × GA + 0.04 mm; R 2 = 0.93) ( P < 0.0001). Conclusion Fetal EFT was greater in diabetics than in nondiabetics, and even greater in pregestational diabetics. EFT maybe an additional and/or earlier marker to identify early changes in fetal metabolism before accelerated fetal growth and polyhydramnios is apparent.