Subinvolution of Placental Sites in Dogs

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4 min read

Key takeaways

Subinvolution of placental sites (SIPS) in dogs is a failure of the uterus to repair itself after birth.

  • The exact cause of SIPS is unknown and occurs most often in dogs under the age of three after a first litter
  • Bloody discharge from the vulva lasting several weeks to months after delivering puppies is the main symptom of SIPS
  • Premature or difficult delivery are potential risk factors for SIPS
  • A presumptive diagnosis requires history, health of the puppies, physical exam, and vaginal cytology
  • Histologic examination of placental sites is required for a definitive diagnosis
  • Treatment is not needed unless bleeding is severe
  • Medications can be used in cases of significant bleeding if the dog is otherwise healthy
  • Severe bleeding may require an emergency ovariohysterectomy if hemorrhage is life threatening
  • Prognosis is excellent for future reproduction if symptoms resolve spontaneously
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A closer look: Subinvolution of Placental Sites in Dogs

Future fertility is not affected if symptoms resolve on their own. Up to twenty percent of reproductively active female dogs are affected with SIPS at some point during their lives. Both mom and puppies are usually otherwise healthy.

SIPS may be suspected any time vaginal discharge continues for more than 6-12 weeks post whelping. Presumptive diagnosis is usually straightforward and prognosis is excellent.

In rare instances bleeding can be severe enough to be life threatening. Any dog with pale mucous membranes, lethargy, or signs of weakness needs prompt veterinary care.

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Risk factors

SIPS occurs most frequently in young, first time mothers. There is no breed disposition.

Dogs are typically otherwise healthy.

In rare cases dogs may experience life threatening bleeding.

Possible causes

The cause of SIPS is not known but the condition occurs most frequently in young, first time mothers. Chances of developing SIPS decreases with each litter.

Premature or prolonged active birth may contribute to SIPS but the causation is not well understood. Research on these topics in canine medicine is scant and information gained is mostly from other species.

Premature parturition can have many causes with uterine infection being the most common cause.

Main symptoms

A diagnosis of SIPS is suggested when vaginal bleeding continues for more than 6-12 weeks after whelping. Both the mother and puppies are usually otherwise healthy.

Normal postpartum vaginal discharge usually varies from having a watered-down bloody red/brown appearance to looking like thick, regular blood. Dogs with SIPS are predisposed to developing vaginal or uterine infections and this may cause the vaginal discharge to change and appear to include pus.

Testing and diagnosis

Presumptive diagnosis of SIPS is based on clinical symptoms and history, vaginal cytology, abdominal ultrasound, and uterine culture.

Definitive diagnosis requires biopsy of the uterus, but this is rarely necessary.

Steps to Recovery

No treatment is typically needed.

Medications may be utilized in an effort to hasten recovery for dogs with more significant bleeding, that develop anemia, or when owners request treatment, but there is little evidence to support their use.

Rarely SIPS can be severe enough to require blood transfusions.

Spaying (ovariohysterectomy) is immediately curative.

SIPS can last for several weeks to months.

Prognosis for life and future fertility is excellent for most cases of SIPS. Prognosis is guarded if the dog experiences life threatening hemorrhage or a uterine infection.


Preventing pregnancy prevents SIPS.

SIPS is not contagious.

Is Subinvolution of Placental Sites in Dogs common?

SIPS is common and occurs in up to twenty percent of births.

Typical Treatment

No treatment is typically needed. If bleeding is severe treatment can consist of:

  • Ovariohysterectomy
  • Blood transfusion
  • IV fluid therapy

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