Maternal glucose loading and fetal cardiac function in humans.

Fetal cardiac function determined using M-mode echocardiography was studied subsequent to the maternal intravenous injection of 20 g of glucose. There were 11 appropriate for date infants (AFD), 7 noneventful, light for date infants (LFD) and one high risk fetus in severe toxemia of pregnancy (Case 1), at 32-40 weeks' gestation. The fetal heart rate showed no significant changes after glucose injection in each group. The left ventricular fractional shortening and cardiac output showed significant changes, whereas the right ventricular fractional shortening and cardiac output were unchanged in both AFD and LFD. In Case 1, the adverse change was noted in both left and right cardiac functions, as compared with AFD or LFD. The combined total cardiac output in AFD increased significantly at 5 min following glucose injection, whereas that in LFD did not change significantly. On the other hand, the combined total cardiac output in Case 1 decreased markedly at 5 min after glucose injection. These findings show that the glucose loading in the mother alters cardiac function in the fetus.