Some specialists reacting to the latest study on bed rest for troubled pregnancies are calling on doctors to refrain from assuming that taking it easy can’t hurt a pregnant woman.

Doctors have known for years that there’s no good evidence in favor of bed rest and the latest research suggests that not only does bed rest not prevent premature birth in troubled pregnancies, it may make things worse.

Nearly 40 percent of the 646 pregnant women enrolled in the latest study were prescribed some type of activity restriction. The surprise: Some 37 percent of women who took the precautions had a premature baby, compared with just 17 percent of the women who didn’t scale back. The research is in Obstetrics & Gynecology.

The latest research has spurred a call for strict studies to finally settle the controversy.