The ideal intrauterine medications cause no irritation to the uterine lining, have broad spectrum antibacterial action, dissolve and distribute rapidly, and have limited systemic absorption. Hormones have also been used to treat retained placentas. Ergot derivatives and estrogens have not been used successfully, and some studies warn against their use. Some studies indicate prostaglandins may decrease the incidence of retained placentas, especially after induced calvings. A short estrous cycle is an estrous cycle less than the normal 18-24 days in length.
Short cycles occur most frequently during the early postpartum period.
As time progresses postpartum, the proportion of estrous cycles of normal length increases. Prostaglandins, released by the uterus, are thought to cause the early regression of the corpus luteum. Postpartum endometrial regeneration and repair may cause increased synthesis of prostaglandins. The prostaglandins produced have a local effect on the ovary containing the corpus luteum and cause its lysis. Postpartum uterine infections have also been shown to cause increased prostaglandins levels.