Active Voice: Exercise for Two—Exercise During Pregnancy Helps Babies Move Better After Birth
By Linda May, Ph.D., FAHA, FACSM

Linda May, Ph.D., FAHA, FACSM
In the U.S., at least one-third of the population is obese. Many pregnant women also are obese at the time of conception. This is problematic since research demonstrates that obese women give birth to obese babies. Thus, the cycle of obesity starts earlier and continues as the child grows.

Related to the intergenerational cycle of obesity, we know that approximately 40 to 70% of obesity is considered heritable. Therefore, 30 to 60% of obesity must be attributed to an environmental component—epigenetic mechanisms. Numerous environmental influences exist, yet two of the predominant mechanisms used to combat obesity are diet and exercise. Although much work has been done with diet and nutrition, let’s focus on exercise, obesity and epigenetics.

It is well known that aerobic modes of exercise help decrease weight (specifically fat), obesity and related symptoms. Currently, ACSM and the American Heart Association (AHA) recommend 150 minutes each week of moderate-intensity aerobic activity for health. Many exercise interventions are provided at various stages of life, from geriatric to preschool-age children, to attenuate obesity and improve health. However, the earliest time to intervene for these positive health benefits is during pregnancy, when the child is first developing.

Empirical evidence consistently supports the idea of fetal origins of health or disease. Thus, the maternal environment can negatively (as in maternal smoking) or positively (as in maternal exercise) program babies toward disease or health, respectively. Based on this idea, many researchers have studied the effects of exercise during pregnancy.

Research continues to demonstrate the benefits of exercise during pregnancy compared to standard care and/or no exercise. Furthermore, 12 systematic reviews of 675 randomized controlled research trials indicate that exercise during pregnancy decreases the incidence of adverse gestational conditions (e.g., gestational diabetes mellitus, hypertensive disorders, preeclampsia, preterm delivery, excessive weight gain, macrosomia). Overwhelmingly, we know that exercise during pregnancy is safe and beneficial for the pregnancy.

In our study, as reported in last month’s issue of Medicine & Science in Sports & Exercise®, my colleagues and I asked whether maternal exercise is beneficial for the baby undergoing development in utero. Our research team wanted to know if, like effects observed in adults, there are specific adaptive changes that might lead to the infant becoming healthier in the future. Being able to move easily is an important component to staying active, so our team investigated the effects of aerobic exercise during pregnancy on the motor skills of 1-month-old infants. Seventy-one pregnant women were randomly assigned to either an aerobic exercise intervention (150 minutes of moderate-intensity activity per week) or no exercise (control). Relative to infants of women who were non-exercisers, the infants exposed to aerobic exercise in the womb had higher scores on four of five neuromotor development variables that we assessed.

These results suggest that participating in aerobic exercise during pregnancy can positively change the developing fetus by improving neuromotor development of the child after birth. This finding is important, since infants who are better movers are more likely to be active as they grow. Given that physical activity is a risk factor of childhood obesity, aerobic exercise during pregnancy may be the most advantageous time to reduce the risk of childhood obesity.

About the author:
Linda May, Ph.D., FAHA, FACSM, was trained as an exercise physiologist at the University of Florida and earned her Ph.D. in physiology at Kent State University. She was the first to publish findings that exercise during pregnancy benefits the heart function of babies. Dr. May is an associate professor in the departments of foundation science and research, obstetrics and gynecology and kinesiology at East Carolina University in Greenville, North Carolina. Currently, her research group studies the influence of exercise interventions during pregnancy on infant outcomes.

Viewpoints presented in SMB commentaries reflect opinions of the authors and do not necessarily represent positions or policies of ACSM. Active Voice authors who have received financial or other considerations from a commercial entity associated with their topic, must disclose such relationships at the time they accept an invitation to write for SMB.