The process of placental delivery and the subsequent involution of the uterus during the puerperium are often described as the third and fourth stages of labor. This chapter presents a brief historical review concerning third- and fourth-stage events, followed by a discussion of the physiology of placental separation and uterine involution. The diagnosis and treatment of retained placenta and membranes (secundines), uterine inversion, postpartum hemorrhage and atony, and hematomas are considered. Important cultural and historical events in world history have been directly influenced by complications of involving the third stage of labor. Active management of the third stage of labor consists of the immediate administration of oxytocin after delivery of the infant, early cord clamping, and gentle traction on the cord, combined with gentle uterine massage to prompt placental separation. Periurethral lacerations, which often bleed freely, appear in the thin tissues on either side of the clitoris or urethra.

Obstetric haemorrhage results in massive blood loss endangering the life of the mother, and the infant in the case of antepartum haemorrhage (APH). This chapter discusses placenta praevia, vasa praevia, postpartum haemorrhage (PPH), uterine atony, genital tract trauma, clotting disorders, and uterine inversion. The Confidential Enquiry into Maternal and Child Health (CEMACH) recommends that all obstetric units have a protocol for the management of obstetric haemorrhage; all individuals working in delivery units should be familiar with local guidelines. APH is a major cause of perinatal morbidity and mortality, including an increased risk of premature delivery. Placental abruption may be partial or complete separation and can occur at any stage of pregnancy. The intervention following placental abruption is dependent upon the severity of the abruption and the presence of fetal compromise. General anaesthesia with relaxation by volatile agents is the most proven anaesthetic technique to correct the inversion.