A client at 39 weeks gestation with preeclampsia has a blood…

A client at 39 weeks gestation with preeclampsia has a blood pressure of 170/100 mm Hg, 2+ proteinuria, and moderate peripheral edema.  Immediately after hospital admission, she develops seizures and uterine contractions.  Magnesium sulfate is prescribed.  Which finding indicates that the drug has achieved the desired therapeutic effect?