Electrocardiographic responses of rat fetuses with clamped or intact umbilical cords to acute maternal uterine ischemia.
Uterine ischemia results in severe cardiac disturbances in the fetus. It has been postulated that these effects are due to interaction between the fetus and the ischemic uterus or placenta, and not to hypoxia or buildup of metabolites in the fetus. Rat fetal cardiac responses to uterine clamping and umbilical cord clamping were compared by electrocardiography. On day 21 of gestation, fetuses in a total of 14 pregnant rats were exposed to umbilical clamping, uterine clamping, or no clamping. Electrocardiograms were recorded for each fetus immediately after clamping and at 10, 20, and 30 minutes after clamping. Immediately after clamping, the uterine clamping group alone showed severe sinus bradycardia. At all other observation times, fetuses exposed to uterine or umbilical clamping showed bradycardia and other electrocardiographic changes typically associated with hypoxia. Therefore, umbilical clamping protected the fetuses from the adverse effects of uterine clamping for only a very short time.
D000818:Animals; D001919:Bradycardia / Q000209:etiology; D003250:Constriction; D004562:Electrocardiography; D005260:Female; D005333:Fetus / Q000502:physiology*; D007511:Ischemia / Q000503:physiopathology*; D011247:Pregnancy; D051381:Rats; D013997:Time Factors; D014470:Umbilical Cord / Q000502:physiology*; D014599:Uterus / Q000098:blood supply*