In does and ewes, the incidence of retained fetal membranes increases with larger litter sizes and with assisted parturition. Systemic treatment to guard against infection and gentle traction on exposed membranes may be used. In sows, retained placentae are contained within the uterus and are not visible at the vulva. In this species, entire fetuses may be retained. Usually, the fetus or membranes decompose in situ. This may be accompanied by signs of systemic illness and a purulent vaginal discharge. Although serious or fatal sequelae occasionally occur, the prognosis for recovery and future fertility is surprisingly good. Antimicrobial treatment is indicated in animals with systemic signs of illness.