Final answer:
During the fourth stage of labor, a client is at risk for postpartum hemorrhage, which can occur if the uterus does not contract properly or if fragments of the placenta remain.
Step-by-step explanation:
A client is at risk for postpartum hemorrhage during the fourth stage of labor. After the delivery of the baby and placenta, the uterus needs to contract to limit blood loss. Proper inspection of the expelled placenta and fetal membranes is crucial to ensure no fragments remain that could cause hemorrhage. Uterine contractions help to reduce blood loss and assist with the involution process of the uterus post-delivery.