Exercise and Pregnancy: Randomized Clinical Trial

The study will include low risk pregnant women randomized to practice physical exercise beginning at 13 weeks, 20 weeks or no exercise group. The objectives are: 1. To describe and compare biological and obstetrical variables. 2. To study doppler flow velocimetry indexes. 3. To determine the association between physical exercise and maternal complications: preeclampsia, preterm labor, gestational diabetes and weight gain in pregnancy. 4. To determine the association between physical exercise and perinatal outcomes: Apgar scores, birthweight, admission at intensive neonatal care unit, body composition and neonatal complications.