"Healthy Bellies" is an intervention program with pregnant women, based on the promotion of healthy lifestyles. It aims to evaluate the impact of the program in the health of both pregnant and newborn. This trial is being conducted with pregnant women, divided into control and intervention group. Are performed 3 assessment periods: 1 - beginning of the program; 2 - postpartum; 3 - 1 month after delivery. The intervention group has a program of 3 weekly physical exercise classes and the control group has the basic information that is usually provided by health professionals. With this program, it is expected to contribute with evidence to the best practice in the field of interventions in pregnancy and improve health outcomes of both pregnant and newborn.

Inclusion Criteria:

• Do not have any medical or obstetric contraindication for physical exercise

Exclusion Criteria:

• Haemodynamically significant heart disease;
• restrictive lung disease;
• incompetent cervix/cerclage;
• multiple gestation at risk for premature labor;
• persistent second or third trimester bleeding;
• placenta praevia after 26 weeks gestation;
• premature labor during the current pregnancy;
• ruptured membranes;
• pregnancy induced hypertension;
• severe anaemia;
• unevaluated maternal cardiac arrhythmia;
• chronic bronchitis;
• poorly controlled type I diabetes;
• extreme morbid obesity;
• extreme underweight (body mass index <12);
• history of extremely sedentary lifestyle;
• intrauterine growth restriction in current pregnancy;
• poorly controlled hypertension/pre-eclampsia;
• orthopaedic limitations;
• poorly controlled seizure disorder;
• poorly controlled thyroid disease; heavy smoker).