[Lung function during tocolysis with beta-stimulators and beta-1-blockers]

The pulmonary function during pregnancy is foremost changed by the elevated diaphragm, which reduces the functional residual capacity. The lungs are less extended, so that the airway resistance increases. The application of a beta-mimetic drug for tocolytic therapy could reduce the airway resistance. Because an additional selective beta-1-blocking drug for cardioprotection could interfere with this effect, the pulmonary function in pregnancy during tocolytic therapy was investigated by body plethysmography in 20 woman of the third trimester of gravidity. There were no apparent differences in the pulmonary function in these woman when an additional selective beta-1-receptor blockade was performed. The airway resistance even diminished during the beta blockade. This unexpected result is probably due to an stabilizing effect of the betablocker on the body fluid and the permeability of capillary membranes during tocolytic therapy.