A nurse performs an assessment of a pregnant woman who is receiving intravenous magnesium sulfate for management of preeclampsia and notes that the woman's deep tendon reflexes are absent. On the basis of this finding, the nurse should make which interpretation?
a) The infusion rate needs to be increased.
b) The magnesium sulfate is effective.
c) The woman is experiencing cerebral edema.
d) The woman is experiencing magnesium excess.