It is possible for any bitch that has not been spayed to exhibit symptoms of pregnancy without actually being pregnant. Some bitches can completely fool their owners with convincing displays of maternal behaviour. Just like a real pregnancy, false-pregnant bitches gain weight, produce milk and make nests. They may be listless, off their food and will often “mother” toys.
It is unclear as to why some bitches experience false pregnancies, but we do know that any bitch that ovulates, whether pregnant or not, will experience the same blood levels of a hormone called progesterone. Around two months after ovulation, the progesterone levels drop and the “milk” hormone prolactin starts to increase in concentration. It is prolactin that is responsible for milk production and maternal behaviour.
False pregnancies generally run a course of 2-3 weeks and treatment is not usually required. In severe cases, where large amounts of milk are being produced, a reduction in daily food intake may help the milk supply to drop. The bitch must not be allowed to lick at her nipples as any stimulation of the mammary glands promotes milk production.
False pregnancies are a normal phenomenon and are not associated with fertility problems. They frequently recur but can be prevented with sterilisation. If the bitch is intended for breeding then she should be bred from her next season and then sterilised once her breeding days are over.