Exercise also may have a favorable effect on the subjective experience of discomfort during pregnancy. In a study tracking
exercise throughout pregnancy,26 women who exercised in the three months before pregnancy felt better during the first
trimester than those who did not exercise. Exercise in the first and second trimesters was correlated with feeling better in the
third trimester. Another study of maternal exercise27 showed a decrease in perceived exertion during labor. No difference was
found in gestational length, maternal weight or duration of the first stage of labor.