Pseudopregnancy (phantom pregnancy; false pregnancy; pseudocyesis) is a relatively common phenomenon in small dogs characterized by pregnancy behaviour, physical changes associated with pregnancy, but the absence of foetuses.
Pseudo pregnancy is a normal physiological process that occurs in female dogs, not usually associated with reproductive organ disorders. It is seen 45-60 days after a normal estrous (heat) period, as progesterone levels, which rise after ovulation, begin to fall. Decreasing progesterone leads to an increase of prolactin, responsible for most of the behaviors seen during a pseudopregnancy episode.
Clinical signs include mothering of toys, nesting, or even aggression. Mammary development and milk production are common.
Mastitis and vaginal hyperplasia are sometimes observed as a complication. Pseudopregnancy can also be acutely induced by spaying a dog near the end of estrus.
Diagnosis is based on the presence of typical clinical signs in metaoestrous non-pregnant bitches.
Treatment usually involves hysterectomy or allowing time for symptoms to abate by normal hormonal resolution.
- Gobello C et al (2001) Study of the change of prolactin and progesterone during dopaminergic agonist treatments in pseudopregnant bitches. Anim Reprod Sci 66(3-4):257-267
- Gobello C et al (2001) Dioestrous ovariectomy: a model to study the role of progesterone in the onset of canine pseudopregnancy. J Reprod Fertil Suppl 57:55-60
- Gobello C et al (2001) A review of canine pseudocyesis. Reprod Domest Anim 36(6):283-288
- Grünau B et al (1996) The treatment of pseudopregnancy in the bitch with prolactin inhibitors metergoline and bromocriptine. Tierarztl Prax 24(2):149-155
- Tsutsui T et al (2007) Plasma progesterone and prolactin concentrations in overtly pseudopregnant bitches: a clinical study. Theriogenology 67(5):1032-1038