Cardiopulmonary Adaptation to Pregnancy

Objective: To examine the cardiopulmonary adaptation to normal pregnancy in sitting women during rest and bicycle exercise
Disign: A longitudinal study beginning early in pregnacy and ending 8-12 months after delivery
Setting: University Hospital Zurich, Switzerland
Subjects: 20 women were monitored every second week during pregnancy from 8-14 weeks of gestataion, twice in the puerperium and twice 6-8 weeks and twice 8-12 months after delivery. All the women finished the study, but not all of them participated in every visit.
1. Most of the cardiopulmonary variables studied had already changed by 8-11 weeks of gestation both at rest and during exercise.
2- Sex to eight weeks after delivery the basic non-pregnant levels are not yet achieved. Thuss, the changes described by several authors who considered 6-8 weeks after delivery as non-pregnant level will be smaller than the true ones.
3. The controversy about adaptation to pregnancy may partly be expained by varied individual responses.
4- The reduced work efficiency during pregnancy contributes to the limitation of reserves needed fpr exercise.
5. None of the variables studied during exercise pointed clearly a risk for maternal or fetal oxygenation. However, the lack of optimal maternal heart rate increase during the last months of pregnancy indicates that the oxygen supply to the working muscles is given preference to the viceral circulation, perhaps including the uterus. This point needs further invesigation.