Abstract:

Objectives:[The goal is] to confirm if physical activity of medium intensity performed during gestation can influence the way of delivery, and observe the adherence to exercise among pregnant women with different education levels. Methods: Held at the Center for Breastfeeding Incentive in the city of São Sebastião, State of São Paulo (Brazil), between April 7, 2008 and April 14, 2009, the prospective study involved 66 primigravid women, who were divided into two groups: the exercise group (GE) that exercised regularly during pregnancy, and the other control group (GC) that did not exercise regularly during same period. The significance level adopted in this study was five per cent (p = 0.05).

Research was conducted at the Maternal Breastfeeding Incentive Center (Centro de Incentivo ao Aleitamento Materno - CIAMA) in São Sebastião, São Paulo, Brazil. The 66 primigravidas were allocated to two groups: a control group, with 29 pregnant women who had not performed any kind of physical activity during pregnancy, and another group, the exercise group, with 37 pregnant women who performed supervised aerobic physical exercises twice a week. These volunteers needed to attend at least 20 sessions to be included in the research. No pregnant women in the control group or the exercise group had performed regular physical activity in the year prior to the pregnancy. All participants received verbal information on how the research would be conducted, and after agreeing to participate they signed a free and informed consent term. The physical activity was prescribed by a physical therapist who remained available to address any doubts about the physical activity and about the research. The study followed the baselines of the American Congress of Obstetricians and Gynecologists (ACOG), where the environment temperature hasn't exceeded 28 °C. The pregnant women were told to wear comfortable clothes and to drink water before and during the activity, and not to perform physical activity while fasting. They were also instructed to interrupt the activity in case they felt dizziness, breathlessness, pain, muscle weakness, dyspnea prior to effort or in case they presented calf swelling or pain, bleeding or signs of labor, or, still, if they noticed decrease in fetal movements. Two weeks after birth the volunteers were contacted by phone to collect information on the type of birth.

The inclusion criteria:

• nulliparae,
• sedentary women,
• ages between 18 and 30,
• gestation age superior to 18 weeks without clinical or obstetrical complications

Exclusion Criteria:

The volunteers in the GE couldn't have a gestation age superior to 20 weeks, had to participate on regular physical activity twice a week, and have a total frequency of at least 20 sessions. The EG pregnant women with frequency inferior to 20 sessions were discarded from the study.

The volunteers in the CG couldn't have performed regular physical activity during pregnancy. In both groups, the participants hadn't performed regular physical activity in the year prior to the pregnancy.

However, 31 women were discarded during the research: three for miscarriage, being two from the GE and one from the GC; one from the GE for anemia; one from the GC for pre-eclampsia; two for loss of contact after birth, being one from each group; 11 from the GE for not reaching the minimum frequency; seven claimed personal reasons for leaving the research, being five from the GC and two from the GE; and six participants abandoned the study.