Final answer:
The nurse should assess for the sign of a prolapsed cord after the spontaneous rupture of membranes in an active labor client, as it is an emergency condition which requires immediate medical attention.
Step-by-step explanation:
When a client in active labor experiences spontaneous rupture of membranes (SROM), also known as "breaking of the water", the nurse should assess for the sign of a prolapsed cord. This is because the rupture can cause the umbilical cord to suddenly drop and become trapped against the baby's body, leading to a decrease in blood flow to the fetus. A prolapsed cord is an emergency that requires immediate medical intervention to ensure the safety of the fetus. Other signs such as increased fetal heart rate, decreased contractions, or meconium-stained amniotic fluid are possibilities after rupture, but the presence of a prolapsed cord is a critical complication that must be ruled out first.