Ventilatory Function in Pregnancy

Abstract

In this investigation 60 pregnant patients underwent serial estimation of forced vital capacity (FVC) and forced expiratory volume (FEV1) throughout pregnancy and after delivery. No significant change occurred in the group mean figures of these measurements of ventilatory function. When patients were divided into those who were non-smokers and those who smoked more than 10 cigarettes daily it appeared that both FVC and FEV1 during the last 8 weeks of pregnancy were slightly reduced in the smokers. Previous studies on the effects of pregnancy upon ventilatory function are reviewed. In this report individual patients had greater variation in both amount and direction of serial recordings than was shown by control subjects. This individual variation may have been responsible for the conflict in some earlier reports which studied smaller numbers of patients. It is suggested that the maintenance of FEV1 and FVC during pregnancy in spite of increasing uterine size and increasing blood volume is the result of hormonal action upon the brain stem, chest wall and lung.