Final answer:
Inspecting the placenta after delivery for intactness is essential to prevent late postpartum hemorrhage.
Step-by-step explanation:
The essential measure to prevent late postpartum hemorrhage is inspecting the placenta after delivery for intactness. By examining the expelled placenta and fetal membranes, the obstetrician can ensure that no fragments remain in the uterus, which could cause postpartum hemorrhage. Administering broad-spectrum antibiotics may be necessary to prevent infection, but it is not directly related to preventing hemorrhage. Manually removing the placenta at delivery may be needed if it doesn't birth spontaneously, but it is not a preventive measure. Applying pressure to the umbilical cord is not a recommended method for removing the placenta.