Abstract 16866: Depressed Biventricular Outputs in Fetuses of Diabetic Mothers When Standardized to Estimated Fetal Weight

Abstract

Background: Although the results of maternal diabetes on the newborn heart are well described, in-utero cardiovascular effects of maternal diabetes and obesity are not as well understood. Hypothesis: Echocardiographically derived measures of right and left heart flow volumes in fetuses of diabetic mothers (FDM) and fetuses of obese mothers (FOM) differ from those of normal fetuses. Methods: We prospectively enrolled 264 normal fetuses, 30 FDM and 49 FOM for prenatal research echocardiography. Estimated fetal weight (EFW) based norms for aortic and pulmonary valve velocity time integrals (AVVTI, PVVTI), right and left ventricular outflow tract diameters (LVOTD, RVOTD), aortic and pulmonary valve stroke volume (AVSV, PVSV), and cardiac output (LVCO, RVCO) were derived from the 264 control group fetuses using nonlinear regression to a Gompertz growth function. Z values for each parameter were determined, then analyzed using a non-paired two-tailed t-test to compare the three groups. Results: The mean ± SD EFW (g) for normal fetuses, FDM and FOM were 1610 ± 1201, 964 ± 694 and 1075 ± 1013; respective mean gestational ages (weeks) were 28.1±1.3, 25.3± 5, and 25 ± 6.6. The table shows mean Z value comparisons of VTI, OTD, SV and CO for the RV and LV in the three groups. Conclusions: FDM have significantly lower right and left heart stroke volumes and outputs than other fetuses matched for size, while FOM did not have demonstrable right or left heart stroke volume or cardiac output changes relative to normal fetuses. Similar to their relationship with gestational age, normal right and left ventricular stroke volumes and outputs follow a non-linear correlation with estimated fetal weight. Flow volumes in macrosomic fetuses may be better normalized to EFW rather than to gestational age. Reduced placental blood flow and ventricular compliance changes may be contributing to depressed biventricular cardiac output in FDM.