[Is orthostatic circulatory regulation more difficult in multiple pregnancy? Results of a prospective longitudinal study].

In 7 multiple pregnancies the changes in maternal and fetal cardiac-circulation parameters resulting from a passive change in presentation from left lateral to steady upright were measured for the duration of pregnancy and the puerperium and compared with corresponding data from a single-fetus collective. The hypothesis that in multiple pregnancies the greater uterine contents lead to more severe problems of return flow from the lower extremities, and that these problems tend to lead a more pronounced form of uterovascular syndrome, was confirmed on the basis of the physiological data. The fact that the uterine contractions usually correlate with the maternal cyclic heart rate accelerations and peak toward the end of the third trimester of pregnancy supports the view that these contractions play a role in regulating circulation.