Etilefrine and amezinium reduce uterine blood flow of pregnant guinea pigs.

Etilefrine and Amezinium are used during pregnancy to prevent hypotension and fetal growth retardation. The effect of these drugs on uterine blood flow (UBF), uterine vascular resistance (UVR) and fetal growth are, however, unknown. 31 guinea pigs were injected daily with Etilefrine (3 X 0.14 mg/kg) and Amezinium (0.14 mg/kg) from day 30 to day 60. Uterine blood flow was measured with radioactive-labeled microspheres. Uterine vascular resistance was calculated from arterial blood pressure and uterine blood flow. 10 guinea pigs treated with 0.9% sodium chloride served as controls. As a response to Etilefrine and Amezinium, UBF fell by 68 and 48%, respectively, accompanied by an increase in UVR. The fetal weight decreased only slightly. It is concluded that long-term application of anti-hypotensive drugs may be hazardous to uterine blood flow and fetal growth.