Pretty much everyone knows about the importance of good nutrition and adequate weight gain during pregnancy. Less is known about the potential health risks, to both mother and child, of excessive weight gain. These include: for the mother, increased chance of a caesarean delivery and obesity later in life; and, for the child, increased risk of pre-term birth and greater chance of obesity throughout life.
A new study in Maternal and Child Health Journal tracks the relationships between exercise, pre-pregnancy and during pregnancy, and excess gestational weight gain. It finds that “exercise during pregnancy is associated with lower odds of gaining excessive weight during pregnancy.”
This healthy correlation did not extend to women who exercised pre-pregnancy, but then stopped after becoming pregnant. The study authors report: “[Our] result suggests that to prevent excessive gestational gain, exercise during pregnancy is more important than exercise before pregnancy.”
The study was conducted among 856 pregnant women in South Carolina, U.S. In 2009, the state introduced a questionnaire that collected both exercise patterns and gestational weight-gain patterns among women who give birth. These women were asked if they exercised at least three times a week. Only one-third of pregnant women met this standard. The researchers also devised an “exercise index” that accounted for exercise amounts across the mothers’ trimesters.
There was little difference between the groups with regard to inadequate weight gain. However, the mothers who exercised more frequently were nearly twice as likely as less frequent exercisers to meet the “adequate weight gain” target, as established by the Institute of Medicine. Also, 51.5 per cent of infrequent exercisers gained too much weight, compared to 35.8 per cent of regular exercisers.
When the researchers applied their exercise index to the subject results, those in the highest third were 80 percent less likely to gain excessive weight than those who did no exercise at all. The high exercisers managed to continue brisk walking, or its equivalent, during five months of their pregnancies.
The authors conclude: “Exercise during pregnancy can help women achieve their recommended gestational weight gain, and experience better maternal and fetal outcomes.”
Study co-author Jihong Liu, of the University of South Carolina, gave Runner’s World this additional advice: “Healthy, pregnant women should exercise the same as non-pregnant women. I recommend walking, easy running, swimming, low-impact aerobics and cycling.”
