It isn’t enough to just quit smoking during pregnancy, say researchers at the University of Washington School of Public Health. Expecting mothers should consider the impact several lifestyle behaviors have on their health and the well-being of their child.

A new study from the School found that pregnant women who maintain total healthy lifestyles – they eat well, stay physically active, have low stress and don’t smoke – are nearly four and a half times less likely to have gestational diabetes.

The study, published online June 22 in the American Journal of Epidemiology, looked at the lifestyle behaviors of 3,005 pregnant women in Washington state. Overall, 20 percent of the women kept a healthy diet, 66 percent were physically active, 95 percent were non-smokers and 55 percent had low stress.

“Our study results suggest that a lifestyle during pregnancy including multiple healthy behaviors can be beneficial for preventing gestational diabetes,” said lead author Sylvia Badon, who conducted the research as part of her doctoral program in the School’s Department of Epidemiology. Badon was named the SPH Magnuson Scholar for 2016-17 and received a $30,000 award to support her studies.

In interviews, participants were asked about the type and frequency of their physical activities, including walking, swimming, dancing, hiking and yoga. They were also asked about their diet over a three-month period, smoking history and status, and handling of stressful and emotional situations.

A numerical value was given to each woman’s answer, with one reflecting a healthy response and zero reflecting an unhealthy response. For example, two and half hours or more per week of moderate to vigorous physical activity was considered a healthy amount and received a one-point score.

Numerical values for each lifestyle behavior – diet, physical activity, smoking and stress – were added and each woman was given a total healthy lifestyle score, ranging from zero to four. When women were tested for gestational diabetes at 24 to 28 weeks pregnant, 140 women were positively diagnosed.

Findings showed that each one-point increase in a woman’s lifestyle score was associated with a 21 percent lower risk of gestational diabetes. Women with a lifestyle score of 0 were 4.43 times more likely to have gestational diabetes than women with a lifestyle score of 4. Women with a score of 4 were 35 percent less likely to have gestational diabetes than women with a score of 3 or less (though this association was not statistically significant).

According to Badon, “Public health and clinical recommendations and interventions targeting multiple components of healthy lifestyle during pregnancy may be more effective in preventing gestational diabetes than approaches focused on a single healthy behavior.”

More than 200,000 women in the United States every year are affected by gestational diabetes mellitus, a common pregnancy complication that causes high blood sugar. Women who develop gestational diabetes are at higher risk of developing type 2 diabetes later in life. Children exposed in utero are at higher risk of macrosomia at birth (being significantly larger than average) and of obesity and type 2 diabetes in childhood and adulthood.

Data were collected as part of the Omega Study, a prospective pregnancy cohort study designed to assess dietary risk factors for pregnancy complications. Participants received prenatal care at clinics associated with Swedish Medical Center and Tacoma General Hospital from 1996 to 2008.

Women completed in-person interviews when they were about 15 weeks pregnant and they were followed until delivery. Pre-pregnancy body mass index was calculated using reported height and weight before pregnancy. Associations were similar for women considered to have a normal weight and those who were overweight or obese.

Women with higher healthy lifestyle scores were more likely to be white, married and first-time mothers. They were also more likely to have a normal weight before pregnancy, at least a high school education and no family history of diabetes.

Study co-authors include Daniel Enquobahrie, Paige Wartko, Raymond Miller, Chunfang Qiu, Bizu Gelaye,Tanya Sorensen and Michelle Williams.

Learn more about Badon and her work to prevent diseases at the 'earliest possible time.'