[Effects of physical exercise on the fetal hemodynamic parameters]

To assess the effects of aerobic physical exercise on the Doppler velocimetry of fetal vessels in pregnant women with no clinical or obstetrical complications.

A cross-sectional study was conducted on 10 healthy low-risk pregnant women at 2 different gestational times: between the 26th and 29th week and 6 days, and at the end of pregnancy, between the 30th and 35th week. The patients were submitted to aerobic physical exercise on a treadmill until reaching fatigue. Ultrasonographic data were obtained at rest and after physical exercise (Doppler velocimetry indices for the umbilical artery, middle cerebral artery, ductus venosus, and uterine arteries). Data were analyzed statistically by the paired and independent Student's t-test using the Statistical Package for the Social Sciences (SPSS) package, version 21.0.

A change in the pulsatility index was observed, with an indication of vasodilatation, with a median value of 1.1±0.1 before exercise and of 1.0±0.1 after exercise; the median value of the resistance index was 0.7±0.04 before exercise and 0.6±0.07 after exercise. The median systole/diastole ratio of the umbilical artery was 3.1±0.4 before exercise and 2.9±0.2 (p=0.03) after exercise at the beginning of pregnancy. No changes in the Doppler velocimetry parameters were observed for the uterine arteries, the middle cerebral artery or the ductus venosus after physical activity at either testing time. Paired analysis of pre- and post-activity data showed a reduction of resistance from the first to the second period (p<0.04).

Physical exercise does not lead to changes in systemic blood flow or fetal-placental flow in healthy pregnant women, confirming that exercises of mild to moderate intensity can be prescribed.