The study included pregnant women, ages 20 to 35, who were divided into two groups. The exercise group did moderate intensity aerobic exercise for at least 30 minutes three times per week while the control group did not get regular exercise.
Researchers from the Kansas City University of Medicine and Biosciences and the University of Kansas Medical Center used non-invasive tests to monitor fetal development, breathing and body movements, as well as fetal heart rate and autonomic nervous system control.
The primary goal of the study was to determine whether exercise during pregnancy resulted in cardiovascular benefits to the fetus while the secondary goal was to determine if exercise during pregnancy increased fetal breathing movements, which is a marker of well-being and of functional development of the respiratory system.
The researchers found that:
• Fetal heart rate was significantly lower in the exercise group during both breathing and non-breathing movement periods.
• Fetal short-term and overall heart rate variability were higher in the exercise group during breathing movements.
• The exercise-exposed fetuses had higher measures of vagal (cardiovascular) control during breathing movements.
• No significant differences in measures of vagal control between the two groups were noted during periods of fetal non-breathing, and there were no group or breathing differences in sympathetic heart rate control.
They concluded that there was a potential benefit of maternal exercise on fetal development because of the link between fetal breathing movements and the developing autonomic nervous system.
I did some pilates exercises on my own, using a "PILATES IN PREGNANCY" book and it did feel good to stretch a bit but I didn't continue with them because these two were so categorical about me not doing any exercises.
I still wonder, even with the studies, what is too much? What is the new research on possible harmful effects on a fetus as a result of vigorous exercise. There has got to be a limit. What is it exactly. I would still want to fall on the side of caution. I would emphasize the fact that pregnant moms should get a clean bill of health without taking on unspecified or unsupervised exercise.
I think the exercises are limited though, as too much exercise might harm you, your baby or both of you. Walking is a pretty simple exercise that is perfect for pregnant. A little Yoga could help too... :)