Having a baby with a healthy birth weight is ideal. Birth weight can have an effect on many factors of lifelong health, including infant mortality, development as a child and even adult health. Giving birth to a baby with a low or a high birth weight can be frightening, as it could affect them for the rest of their life. For many years, people have questioned whether or not physical activity of the mother during gestation has any effect on healthy birth weights. It seems like it would make sense, since physical activity leads to a healthy weight for individuals. However, the results of a recent study show that such a logical connection with fitness and weight does not apply to developing babies.

In the study, pregnant women were asked to join an exercise program that consisted of supervised aerobic dance and strength training for one hour twice per week, plus an additional 30 minutes of physical activity on all other weekdays. The birth weights of their babies were compared to those of women who were sedentary, and there was no difference. The aerobic and strength exercises had absolutely no effect on the birth weight or newborns, neonatal birth rate or even neonatal well-being. If you are looking to guarantee a healthy birth weight for your baby, exercise will not actually have any effect.

However, this doesn’t mean that you shouldn’t exercise while you are pregnant. The results of the study showed that such regular exercise is completely safe. The positive benefits of exercise are well known and far-reaching, so pregnant women should reap these benefits as much as they can. Healthy bodily function and a better mood are only the very basic reasons that women should exercise, even when pregnant.

The results of this study show that, although it seems logical, your physical activity while bearing a child will have no effect on the birth weight of your baby upon delivery. Birth weight is not associated with the mother’s fitness, and tips on promoting a healthy birth weight should be further researched. Genetics, number of previous births, maternal age, pre-existing medical problems and gestational diabetes are all proven to have more of a bearing on a baby’s weight. However, exercise during pregnancy is perfectly safe, and it should be considered as a method for maintaining a positive mood and a healthy bodily state for the duration of gestation.

Source: Lene Haakstad et al: Exercise in Pregnant Women and Birth Weight. BMC Pregnancy and Childbirth Volume 11 September 2011