Pseudopregnancy in the bitch

Pseudopregnancy in the bitch is a normal phenomenon. It refers to the dioestrus phase of the bitch's reproductive cycle. It can range in severity from covert pseudopregnancy, in which the signs are barely noticeable, to severe clinical or overt pseudopregnancy. It occurs six to eight weeks following oestrous. The bitch may present with pregnancy-like behaviour including nesting and aggression, excessive mammary enlargement and contractions. These signs are an exaggerated version of the normal signs shown in a normal entire cycling bitch. The exact aetiology behind pseudopregnancy is not known. It is believed to be associated with a rapid decline in serum progesterone concentrations and the resulting surge in prolactin. Treatment may involve conservative management, medical therapy or ovariectomy/ovariohysterectomy. In the past medical therapy has included sex steroids including oestrogens, androgens and progestins. However, due to the frequent incidence and severity of side effects their use is contraindicated. Recommended forms of management incorporate the use of prolactin inhibitors such as cabergoline, metergoline and bromocriptine. These drugs reduce serum levels of prolactin and therefore reduce the development of mammary glands and decrease the behavioural signs associated with overt pseudopregnancy.