Sub Involution of Placental Sites in Female Dogs

Sub involution of placental sites (SIPS) is a postpartum reproductive disorder primarily seen in bitches, where the placental attachment sites within the uterus fail to properly heal and regress after parturition.

In the bitch (female dogs), during the post parturient period it is normal to have a serosanguineous vaginal discharge for up to 3-6 weeks. Sub involution of placental sites (SIPS) is suspected if a sanguineous vaginal discharge persists for longer than 6 weeks.

SIPS almost exclusively affects the young primiparous animal.

Clinical Signs

• Vaginal discharge beyond 6 weeks without any complication
• Bitches usually do not show any symptoms of illness
• Vulva may be slightly enlarged and flaccid
• Vaginal mucosa normal

Diagnosis

• Rarely, abdominal palpation reveals single or multiple discrete, firm, spheroid enlargements spaced along the length of the uterus.
• These palpable structures are large eosinophilic masses protruding in to the uterine lumen from the endometrium.
• These lesions are raw and ooze blood, accounting for the vaginal discharge.
• They represent a failure of slough these eosinophilic masses of collagen, which is part of the normal involution healing process of the endometrium, accounting for the descriptive name “Sub involution of placental sites”.
• Vaginal cytology may reveal syncytial trophoblast-like cells, which aids in confirmatory diagnosis.

Differential Diagnosis

Prolonged post partum vaginal bleeding should be differentiated from:

• Metritis
• Vaginitis
• Coagulopathies
• Proestrus
• Trauma
• Neoplasia
• Cystitis

Treatment

• Bitches with persistent small amount of hemorrhagic vaginal discharge postpartum usually do not require any treatment.
• Some recommend use of antibiotics; helpful only if infection is present.
• Curettage via hysterotomy.
• Prostaglandins (natural) 0.25 mg/kg, once daily for 4-5 days may be tried.
• Injection of oxytocin following whelping has been suggested to aid in preventing SIPS.
• In rare cases of profound permanent bleeding or uterine infection, ovariohysterectomy is indicated.