Vet at FirstVet answers:
False pregnancy occurs naturally in the bitch. It takes place 6 to 8 weeks after heat and is identified as having swollen milk-filled mammaries, increased tendency to collect, carry and nest things, decreased physical activity, and disinterest in going on walks. False pregnancy goes away on its own, and by 3-4 months following heat the bitch should no longer have any symptoms. Medication to rid the symptoms of false pregnancy exists; if milk production is excessive or the bitch is psychologically affected it may be wise to consider treatment. It can also be a good idea to spay a bitch that suffers from troublesome false pregnancies.