Canine Retained Placenta Study Guide

Overview and Clinical Importance

Retained placenta (also called retained afterbirth or retained fetal membranes) occurs when the placenta is not expelled from the uterus within the expected timeframe following parturition. In dogs, the placenta should be expelled within 15 minutes of each puppy's delivery. Retained placental tissue can rapidly become a nidus for bacterial infection, potentially leading to metritis, sepsis, and death if not promptly recognized and treated.

This condition is relatively uncommon in dogs compared to large animal species but carries significant morbidity when it occurs. Retained placenta is particularly important on the NAVLE because it tests your understanding of canine reproductive physiology, postpartum complications, and emergency medicine principles.

Canine Placental Anatomy and Physiology

Placental Classification

The canine placenta is classified as zonary (by gross morphology), lamellar (by internal architecture), and endotheliochorial (by histological barrier). The zonary placenta forms a circumferential band around the equator of the chorionic sac, creating an intimate attachment to the endometrium at this region.