14 pregnant women were investigated of the age of 24-33 (on the 26th pregnancy week) and 12 not pregnant women of the age of 24-33. Women who were investigated were divided into 3 groups: the first group consisted of 7 pregnant women who did exercises in the water for 60 minutes 3 times a week; the second group – 7 pregnant women who didn’t do exercises in the water; and the third group – 12 not pregnant women who didn’t do exercises. All the three groups did load of the same physical intensity which was gradually increased with using veloergometre “ Monak 834 E Ergomedic”, with mask of gas analyzer “ Oxycon Mobile” which ascertained spiroergometrical index ( lung ventilation, oxygen uptake, breath volume, breath rate, the maximum oxygen pulse, coefficient of respiration) and the pulsometre “ Polar Accurex- Puls”, which registered heart rate. After the load in the 1th and 2th groups of pregnant women the foetus heart rate was registered by the electronic stethoscope. The results of our investigation showed that gymnastic exercises have a positive effect upon the aerobic capacity of pregnant women. The length of child – birth is shorter of pregnant women who do exercises and also complications is less than of not exercised pregnant women. All the women who were investigated gave birth to healthy new born babies; however the weight of new born babies of pregnant women who did exercises was smaller.