TL;DR: A retained placenta occurs when afterbirth remains in the uterus post-delivery, which can lead to life-threatening infections like metritis. If you suspect a placenta is missing two hours after the last kitten is born, contact your veterinarian immediately for guidance.
What does it mean if my cat has a retained placenta?
A retained placenta occurs when the afterbirth—the organ that supplied nutrients to the kitten during pregnancy—remains inside the mother's uterus instead of being expelled. Normally, one placenta should be delivered for every kitten born, though sometimes a mother cat (queen) will deliver two kittens followed by two placentas. If you are certain a placenta is missing two hours after the last kitten, it is medically classified as retained.
Is a retained placenta a medical emergency for my cat?
- The urgency level for a retained placenta at the two-hour mark is Medium, requiring prompt veterinary consultation.
- If the tissue is not expelled, it can lead to a severe bacterial infection called metritis.
- Watch for warning signs like extreme lethargy, foul-smelling discharge, or a mother ignoring her kittens, as these indicate a high-priority emergency.
How can taking a photo help the veterinarian triage my cat's condition?
- Take a photo of any expelled tissue or the vaginal area if you are unsure if the placenta was passed or eaten.
- Share these photos with a veterinarian to confirm if the tissue appears complete or if there are signs of partial retention.
- This visual evidence helps determine if your cat needs an immediate office visit or if it is safe to continue monitoring at home.
Clinical Context (Merck Veterinary Manual)
In queens, after 2 hours if retained placentae are suspected, treatment includes supportive care and antibiotic therapy based on culture and sensitivity testing of the vulvar discharge in cases with signs of systemic illness or abnormal vaginal discharge. Radiographs should be taken to determine whether placentas are retained. Oxytocin (2-5 U, IM) may help evacuate the uterine contents. Ovariohysterectomy is recommended after initial stabilization if the animal is extremely ill or if future reproduction is unimportant; otherwise, it should be considered an elective procedure when lactation has ceased. Prostaglandin F2a (0.1-0.25 mg/kg, SC, for 2-3 days) or cloprostenol (1-3 mcg/kg, SC, every 12-24 hours to effect) can usually induce passage of the placenta.
Chapter: Reproduction, Infectious Disease
Source: The Merck Veterinary Manual, 11th Edition (Page 1382)