Influence of thiopental anaesthesia on fetal motor behaviour in early pregnancy

Abstract

Real-time ultrasonography has shown fetal motor activity to be present long before the mother is able to perceive any movements. The development of fetal movement patterns reflects neuromotor maturation of the fetal central nervous system. Drugs given to the mother may affect fetal neuromotor behaviour. In 20 first trimester pregnant women, applicants for legal abortion, fetal movements were objectively recorded before and after thiopental anaesthesia, using a semi-automatic method for quantitative recording of fetal movements displayed in real-time ultrasound image of the uterus. In ten patients randomly selected for premedication with morphine-scopolamine 1 h before surgery, fetal motor activity was practically abolished after the thiopental injection. In the other ten patients not so premedicated, the abolishment of fetal movements was delayed by 3 min. During the second minute after the thiopental injection, there was an increase both in the number and incidence of movements, as compared with the control period. In the latter group there was a positive correlation between the number of fetal movements and thiopental concentrations both in maternal plasma and placental tissue. The present method might be used for description of the pharmacodynamic effect of a drug distributed to the mother and traversing the placenta.