Maybe, to cool off? I notice when my dogs get too warm on the couch or on blankies, they flop on the hardwood floors or bathroom tile floors.
Just my guess? I always say mine are having hot flashes, due to decline in estrogen, common in spayed gals, as well as the aging ones.
I believe in spaying and neutering. Lord knows there is enough dogs and cats in the shelters due to unwanted or unexpected pregnancies. Also, if breeders aren't going to breed within 1-2 yrs of the *****'s optimum breeding time, they should and usually have the ***** spayed.
Hope your gal has a safe delivery, and y'all get some relaxation and peace of mind. Keep us updated.