- Because the potential effect of the programmed maternal physical activity during pregnancy over the sleep duration or over the poor-sleeper-newborn answer to the sleep trial is not known, newborns to mothers that participated at the PAMELA trial will not be eligible to the sleep trial. The PAMELA (Physical Activity for Mothers Enrolled in Longitudinal Analysis) is a randomized controlled trial nested in the Pelotas 2015 birth cohort planned to assess the effect of regular exercise during pregnancy on the prevention of hypertension, pre-eclampsia and preterm birth. Eligible pregnant women between the 16th and 20th week of gestation are allocated into control group (426 women who are advised to keep their usual daily activities) or intervention group (213 women who engage in an exercise program, three sessions a week).