Low levels of blood alcohol and fetal myocardial function.

In ten experiments carried out on five chronically catheterized pregnant ewes (130 to 140 gestational days), 0.8 ml/kg absolute ethyl alcohol was injected into the mothers over a ten-minute period. Peak maternal and fetal alcoholemia levels were 1.1 +/- 0.1 and 0.9 +/- 0.04 g/L, respectively. Blood gases (arterial PO2, PCO2, pH, and arterial O2 content), cardiovascular parameters (heart rate, arterial pressures), and fetal myocardial function (systolic time intervals) were studied at basal state and during the four hours after injection. To observe changes in fetal O2 affinity, 2-3 diphosphoglycerate concentration and P50 were assessed before and at the peak of blood alcohol level. Maternal and fetal blood ethyl alcohol levels correlated closely (r2 = 0.9512) during all experiments. A small increase in the fetal arterial pH and a decrease in maternal PCO2 was observed just after the injection. This low level of fetal blood alcohol caused a moderate but significant decrease in myocardial contractility as judged by the changes in systolic time intervals. There was no alteration of other cardiovascular parameters and of hemoglobin oxygen affinity.