Do fit moms give birth to babies with a healthier weight?

A study involving 84 women pregnant with their first child found that physical exercise was associated with slightly lighter babies.

As excess weight and obesity continue to spread through the population, the number of overweight future mothers also increases. This does not only affect the mother’s health, but the baby’s as well. Among other things, these women are more likely to give birth to big babies, who will be at a greater risk of developing various health problems throughout their lives. Regular physical exercise during pregnancy may offer advantages for the baby’s future health by keeping body weight under control in the womb.

A study involving 84 women pregnant with their first child found that physical exercise was associated with slightly lighter babies. The researchers asked half the women to use a stationary bicycle for five 40-minute sessions each week until at least the 36th week of pregnancy. The women who did regular physical exercise had babies that were as long on average as those of the inactive women, but their babies were 143 grams lighter on average. These findings suggest that moderate physical exercise did not stunt the babies’ growth in the womb, but that it reduced the amount of fat the babies accumulated. In addition, regular use of the exercise bike did not seem to interfere with the natural changes in the mothers’ response to insulin, which is an essential mechanism in pregnancy to ensure the foetus is properly nourished.

An increasing number of studies are finding that a child’s future metabolism may be influenced by the environment in the womb, and that babies who are relatively heavy for their length may be more likely to become obese. Slightly reducing their birth weight may therefore offer long-term health benefits for newborns.

The recommendation in Canada is for women to continue to practice regular physical activity during their pregnancy, as it is for any healthy individual. Benefits of staying active include improving mood and body image, avoiding the accumulation of excess weight, promoting sleep, relaxation and stress relief, keeping the body in shape for the delivery and increasing the woman’s overall energy level. However, it is important to remain well hydrated, avoid high-impact activities and adapt your effort to your energy level.