Fetal cardiac function and septal thickness in diabetic pregnancy: a controlled observational and reproducibility study

Objective: To determine the reproducibility of duplex Doppler waveform analysis and fetal cardiac interventricular septal thickness measurement and to compare these parameters in matched pregnancies with and without well-controlled maternal Type 1 diabetes at 18–20 weeks of gestation.Design: A prospective blind twin cohort study and a blinded inter-observer and intra-observer agreement study.Setting: A tertiary referral prenatal diagnostic unit within a university hospital.Results: Good inter- and intra-observer agreement was found for the measurement of transvalvular peak flow velocities and the duration of ventricular ejection in the fetal heart. Inter-observer agreement for aortic flow acceleration rate was poor. M-mode measurement of interventricular septal thickness showed moderate reproducibility. The mean (SD) width of the interventricular septum in the fetuses of well controlled diabetic women was 2.1 mm (0.2 mm), and was significantly greater (P= 0.01) when compared with the corresponding value in matched controls [1.9 mm (0.2 mm)]. No cardiac functional differences were evident.Conclusions: On-screen video analysis of Doppler cardiac flow waveforms and M-mode measurement of intraventricular septal thickness demonstrated good reproducibility. The fetuses of well controlled diabetic pregnancies demonstrated signs of altered cardiac morphology early in pregnancy, before any evident alterations in cardiac function.