Maternal and fetal plasma renin activity during ritodrine infusion to the mother.

The effect of ritodrine to the mother on plasma renin activity (PRA) in the mother and fetus was examined in 10 mothers coming to elective cesarean section. 10 comparable mothers without ritodrine infusion served as controls. At the end of 2 h infusion of ritodrine, the mean maternal PRA was significantly (p less than 0.001) higher than in the control group. Also the mean PRA levels in the umbilical vein (p less than 0.001) and umbilical artery (p less than 0.01) were significantly higher after ridodrine infusion to the mother than the respective levels in the control group.