Tococardiography in pregnancy during extracorporeal bypass for mitral valve replacement.

A 23-year-old pregnant woman with class III rheumatic heart disease, with mitral stenosis, underwent mitral valve replacement with cardiopulmonary bypass during the 32nd week of gestation. Fetal heart rate and uterine activity were recorded during the operation. Transient fetal heart rate decelerations and loss of variability, as well as uterine contractions, were observed during surgery and subsided spontaneously afterward. The pregnancy was carried to term and resulted in a normal infant. Problems associated with maternal extracorporeal circulation during pregnancy are discussed. Long-term effects on the fetus are presently unknown.