Pregnant women are often told to sleep on their left side to reduce the risk of stillbirth, but new research suggests they can choose whatever position is most comfortable through most of the pregnancy.

“We can reassure women that through 30 weeks of pregnancy, different sleep positions are safe,” said study lead author Dr. Robert Silver, chairman of obstetrics and gynecology at the University of Utah School of Medicine.

Silver said the study didn’t include women past 30 weeks, so researchers can’t make any definitive statements about the last weeks of pregnancy.

The research is being published in the October issue of Obstetrics & Gynecology and ahead of print online Sept. 10.