Sitting down for too long may cause expecting mothers to feel blue, according to a recent study.

Researchers from the University of Warwick in the United Kingdom and George Eliot Hospital NHS Trust found that those suffering from symptoms of depression during pregnancy are more likely to sit down for long periods of time in the second trimester. They also found this puts them at risk of greater weight gain and contracting gestational diabetes.

"Pregnant women could benefit from early intervention to improve their physical and mental health and reduce the risks associated with sedentary behavior," Dr. Nithya Sukumar, who led the study, said in a statement. "Gestational diabetes can increase the risk of birth complications for the mother and baby and so it is important we minimize this risk by reducing the time that pregnant women spend sitting down."

Previous studies have linked sedentary behavior linked to diabetes, obesity, heart disease and mental health problems, but its impact on the health of pregnant women is unclear.

For the study, Sukumar and her colleagues collected and analyzed data from more than 1,200 pregnant women. The participants were asked to report on their level of physical activity and emotional wellbeing in the first trimester of pregnancy and then again in the late stages of the second.

They found that overall, women with self-reported depression symptoms were more likely to sit down for longer periods -- despite accounting for their body mass index, age and socio-economic status. Pregnant women who spent more time sitting down in the second trimester also did fewer amounts of moderate or vigorous physical activity, and sedentary women gained significant amounts of weight between the first and second trimester.

They also found that sedentary pregnant women had higher blood glucose levels around 28 weeks of gestation, putting them at higher risk of developing gestational diabetes.

"Encouraging women to take breaks from sitting down might be an easier public health policy to implement than increasing their physical activity during pregnancy. We believe reducing the sitting time has the potential to reduce pregnant women's risk of gestational diabetes and reduce the metabolic risk factors of their newborns," researcher Dr .Ponnusamy Saravanan said in a statement.

The findings were presented at the Society for Endocrinology annual conference in Edinburgh.