Surgical preparation of a chronic maternal-fetal model in pregnant sheep: A technique for the measurement of middle uterine blood flow, umbilical blood flow, and fetal sampling in the awake sheep

Abstract

A surgical technique has been described for the preparation of a maternal-fetal model in the pregnant sheep. This preparation allows the measurement of maternal middle uterine arterial blood flow, fetal umbilical blood flow, maternal and fetal arterial blood pressure, and the sampling of fetal artery and vein and the maternal circulation in the unstressed animal. Blood gas data and electromagnetic flow data indicate that a 48-hour postsurgical period was necessary for complete recovery of the fetus from preparative surgery and anesthesia. This model enables the study of the fetal and uterine circulation without the stressful effects of preparative surgery and anesthesia.