Assumption: Bed rest can prevent miscarriage.
Bed rest has not been proven to prevent miscarriage. In this group of 84 women, there was no statistical difference between women on bed rest and those not on bed rest. Clearly, the sample is small, so more studies are needed, please!
Although it may be good for women to slow down if they are facing a possible miscarriage, ultimately it probably will not prevent the miscarriage from happening. My personal belief is that miscarriage is usually not caused by being active, so while slowing down and taking it easy may be better for the mother’s health, it will not change what is happening with the baby.