ABSTRACT
A total of 177 M-mode echocardiography studies were done on three groups of fetuses
at different gestational ages: group I, normally grown fetuses; group II, intra-uterine
growth-retarded fetuses (IUGR); and group III, fetuses of diabetic mothers. Adjusted
for gestational age and for fetal weight, the hearts of fetuses with IUGR were found
to have an increased minor axis dimension due to free wall hypertrophy. No ventricular
dilation was found in this group. Furthermore, IUGR fetuses have a larger heart proportionally
to their body weight, raising the possibility 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. The increase was
secondary to free wall hypertrophy, interventricular septal 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 size. The free wall hypertrophy found in these two groups may occur by different
processes, which needs to be further investigated.
