Effects of pregnancy on the electrocardiogram in healthy subjects during strenuous exercise

Pregnancy may normally be associated with electrocardiographic changes during exercise. Researchers obtained electrocardiograms from 39 pregnant women in early and late pregnancy and from eight nonpregnant women during bicycle exercise tests. Pregnant women exhibited more T-wave inversions in V2 than nonpregnant women. In late pregnancy, women had much fewer small Q waves. Pregnant women achieved maximum ST depression much sooner than nonpregnant women during exercise. Pregnant women did not experience any adverse cardiac effects from exercise.