
I have never had severe phantom symptoms in any of mine, just the usual slightly swollen mammary glands, easy too miss with a double coted breed, and most noticeable after first season when all the reproductive parts become more obvious thereafter.
Have never found them any worse, if anything better after be4ing bred from, so I wouldn't rush into neutering following first litter, but see how subsequent seasons go.
You won't be able to evaluate her offspring fully, to decide if you want to breed again, FOR AT lLEAST A YEAR OR SO.