
Phantom pregnancy is the natural result of being in season, bitches are actually designed to do this, as in the pack situation they would help feed the packs litter.
Thankfully most bitches have minimally distressing symptoms, just a bit of mammary swelling, maybe a little milk that gets absorbed if left alone.
Others go the whole hog. I have never had a bitch with obvious phantoms yet had excellent mothers so can't answer that part.