FETAL CARDIAC SIZE IN NORMAL, INTRAUTERINE GROWTH-RETARDED, AND DIABETIC PREGNANCIES

A total of 177 M-mode echocardiography studies were done on three grou ps of fetuses at different gestational ages: group I, normally grown f etuses; group II, intrauterine growth-retarded fetuses (IUGR); and gro up III, fetuses of diabetic mothers. Adjusted for gestational age and for fetal weight, the hearts of fetuses with IUGR were found to have a n increased minor axis dimension due to free wall hypertrophy. No vent ricular dilation was found in this group. Furthermore, IUGR fetuses ha ve a larger heart proportionally to their body weight, raising the pos sibility of a ''sparing effect'' in this particular group. The hearts of fetuses of diabetic mothers were also found to have a significantly larger cardiac size than that of a group of normally grown fetuses. T he increase was secondary to free wall hypertrophy, interventricular s eptal hypertrophy, and right ventricular dilation. This study confirms previous reports about fetal diabetic cardiomegaly and documents the contribution of the different cardiac components to this increase in s ize. The free wall hypertrophy found in these two groups may occur by different processes, which needs to be further investigated.