Sub involution of Placental Sites (SIPS): a Postpartum Disorder in Bitches

After parturition, Uterus will revert back to preconception state termed as involution of uterus. The normal time taken for uterine involution varies from species to species, in dogs it will take about 3 ½ to 4 months. There are many postpartum or puerperium disorders that can occur after parturition in dogs (whelping) like Eclampsia (Most Frequent), SIPS, Metritis, PPH etc. Sub involution of Placental Sites (SIPS) is seen in bitches that whelped for first time. It is characterized by delay in uterine involution due persistence of syncytial trophoblasts (some consider them as decidual cells) followed by deep invasion of these cells into uterine wall (endometrium, sometimes into myometrium) causing leakage of blood in to uterine lumen and postpartum discharge to remain active even after 6 weeks of parturition. Normally when the dog is presented to a physician with the persistence of postpartum discharge even after 6 weeks (sero-sanguineous discharge), first condition to rule out is SIPS.