VCP 411: Gynaecology and Obstetrics Section

Sub involution of placental site

SUB INVOLUTION OF PLACENTAL SITE (SIPS)

• Bitch presented with bloody discharge 6 weeks post whelping.
• Sub involution of placental site is the failure of one or more placental site to involute or disappear at the appropriate time after parturition.
• Bitches normally discharge lochia for apparently 4 to 6 weeks post partum.
• The uterus returns to normal size approximately 9 weeks post partum and uterine involution is histologicaly complete by 12 weeks post partum.
• In sips the post partum hemorrhage continues for 8 to 16 weeks after whelping which is due to failure of normal thrombosis and normal occlusion of endometrial blood vessels caused by damage to these vessels by persistent of trophoblast like cells.