Final answer:
The patient with hydramnios undergoing an amniotomy is at risk for abruptio placenta, a complication that can lead to fetal hypoxia. Placenta previa is not directly related to hydramnios or amniotomy.
Step-by-step explanation:
When a patient who has been diagnosed with hydramnios undergoes an amniotomy, the nurse needs to be aware that the patient is at risk for a complication called abruptio placenta. Hydramnios, also known as polyhydramnios, is a condition characterized by an excess of amniotic fluid. This excessive fluid can cause the uterus to overdistend, which increases the risk of the placenta detaching from the uterine wall prematurely, leading to abruptio placenta. This condition is associated with severe bleeding and can pose significant risks to both the mother and the fetus, including the risk of fetal hypoxia, where the baby's oxygen supply is compromised. In the context of the provided information, although placenta previa (a condition where the placenta partially or completely covers the cervix) is a known pregnancy complication, it is not directly associated with hydramnios or amniotomy procedures, as this condition is related to the implantation site of the placenta.