As many as 20 percent of women are prescribed bed rest for a period of time during their pregnancies, ranging from a few days to multiple months. Usually the concern is threatened premature labor, which could result from a specific condition or occur without warning.
So why bed rest? Well, it seems logical—surely laying down and not jostling so much is a good idea! And if you know someone who has been on bed rest and went on to have a healthy, full-term delivery, it may look like it worked. Many women who are put on bed rest go on to have their babies at a normal time.
But, and I cannot stress this enough, that is not evidence that it works. We don’t know what would have happened if those women engaged in normal activities. In fact, there is no compelling evidence to suggest that bed rest is effective at preventing preterm labor.