Recommendations for exercise developed by the Centers for Disease Control and Prevention and American College of Sports Medicine were established about15 years ago, and it has been 9 years since their adoption by the American College of Obstetricians and Gynecologists. Finally, new recommendations have been suggested.
Specifically, the safety guidelines during pregnancy suggested by the authors are as follows: with respect to muscle strengthening, in pregnant adults aged 18 to 45 years of age: “8 to 10 muscular strength exercises can be performed for one to two sessions per week on nonconsecutive days. One aerobic training session can be replaced by a muscle strengthening session in the weight room or at home,” they suggest.
The authors also recommend using lighter weights with more repetitions. “Heavy weights may overload joints already loosened by increased levels of the hormone relaxin during pregnancy,” they note.
Walking lunges, which may raise the risk for injury to pelvic connective tissue, and free weights, which may hit the abdomen when used, should be avoided. Instead, the authors recommend the use of resistance bands.
In addition, lifting while flat on one’s back, in the second and third trimesters, may cause the uterus to compress the inferior vena cava, into which blood from the pregnant uterus flows. “This increased pressure can be transmitted to the placenta and could compromise fetal blood flow in the gas-exchange area, thereby limiting oxygen supply to the fetus.” Instead, these movements can be performed at an incline.
The Valsalva maneuver, that is, forcefully exhaling without releasing air, can rapidly increase blood pressure and intra-abdominal pressure and also may decrease oxygen flow to the fetus. Rarely, the Valsalva maneuver may result in a decrease in blood pressure.
As with all medical advice, consult your doctor before implementing any of these recommendations.
J. Kyle Mathews, MD
Plano OB GYN Associates