[Study of resistance to physical stress in pregnant women: influence of standardized work on cardiovascular system, ventilation, gaseous interchange, carbohydrate metabolism and acid-base balance (author's transl)].

10 women in the 12th week of pregnancy were tested with 50 and 60 watts on the bicycle ergometer; 16, in the 38th week of pregnancy and 12 weeks after delivery. Heart rate, blood pressure, O2 intake, CO2 elimination, respiration rate, respiratory volume per minute, lactate, pyruvate, glucose, pCO2, base excess and pH were measured at rest and under stress. Already in the 12th week of pregnancy (SSW), O2 intake and calorie consumption for the same work was significantly higher than in the nonpregnant subjects. Heart rate and blood pressure behaved the same during and outside of pregnancy. In the 38th week of pregnancy, the steady-state was reached later. O2 intake and calorie consumption were significantly increased. In pregnant women, the glucose level decreased about 11 mg% under stress while it remained constant in nonpregnant subjects. In pregnant women, lactate production is significantly higher (26%) during work. Metabolic acidosis cannot be compensated by respiration. The base deficit was significantly larger; pH was reduced. In pregnant women, physical stress produces increased respiration, CO2 consumption and calorie consumption are increased, CO2 deficit is greater and metabolic acidosis develops.