There have long been differing opinions on the effects -- both potentially positive and negative -- of exercising while pregnant. It's something that you may be hesitant to do, for fear of endangering your unborn child. Fortunately, there have been myriad studies and scientific medical reports on the effects of exercises during pregnancy, as well as which sorts of exercises are preferable.
Low-Impact Aerobics
According to a 2005 study conducted at Malmö University Hospital in Sweden, low-impact aerobic exercise was not found to present any additional risks to pregnant women or their unborn children. The study, led by L. Larsson and published in the journal "Acta Obstetricia et Gynecologica Scandinavica," concluded that such activity doesn't heighten risks of neural tube defects because no women in the study approached dangerously high body temperatures.
Some examples of low-impact aerobics, which the study defined as engaging 70 percent of maximum heart rate, include slow or medium-paced swimming and walking.
Benefits
Research led by Capt. Marlene DeMaio at the Naval Academy in Portsmouth, Virginia, concluded that pregnant women are safe exercising, but only if they're in good health and not engaging in high-impact exercise.
According to the research, exercise during pregnancy can benefit expectant mothers by reducing back pain, lowering blood pressure and reducing swelling, without the risk of damaging the fetus. Researchers noted, however, that pregnant women should avoid collision sports and deep-sea diving, and should only do non-weight bearing exercises, such as swimming and stationary biking, in the final three months of pregnancy.
Potential for Reduced Size of Offspring
Exercising during pregnancy may reduce the size of the baby when born, according to a study co-led by Sarah A. Hopkins of the University of Auckland in New Zealand and published in the October, 2010, "Journal of Clinical Endocrinology & Metabolism." According to the study, exercise may affect the way nutrients reach the fetus, resulting in smaller-sized babies. An increased size at birth is related to a greater chance of developing obesity later in childhood, and co-author Paul Hofman notes a "modest reduction in birth weight may have long-term health benefits for offspring by lowering this risk in later life."
The study did not note any causal relationship, though, between exercise and babies being born with birth defects or shorter in length.
Expert Insight
Drs. Thomas Wang and Barbara Apgar of the American Academy of Family Physicians report that the difference in heart rate between exercising and non-exercising pregnant women is not substantial enough to present any risks. Additionally, they say there is no evidence that exercise increases levels of hormones that could result in premature birth. But the doctors warn not to engage in activities that involve sudden changes in position or vast ranges of motion.
Depression
Because of the chemical changes that come with pregnancy, some pregnant women suffer from depression or mood swings. According to the American College of Obstetrics and Gynecology, between 14 percent and 23 percent of women suffer from depressive symptoms during pregnancy. Exercising may benefit pregnant women in this regard, because it increases levels of serotonin, a chemical that occurs naturally in the brain and stimulates the nervous system.
References
- PubMed.gov: Low-Impact Exercise During Pregnancy
- LiveScience: Study: Healthy Pregnant Women Should Exercise
- ScienceDaily: Exercise in Pregnancy Reduces Size of Offspring, Study Suggests
- American Academy of Family Physicians: Exercise during pregnancy
- American College of Obstetrics and Gynecology:
- Journal of Clinical Endocrinology & Metabolism: Exercise Training in PregnancyReduces Offspring Size without Changes in Maternal Insulin Sensitivity
