单选题 Mrs. S with preterm labor will be under Terbutaline (Brethine) therapy. Before beginning the therapy, which of the following assessments would be most important

A、 Estimated fetal size.
B、 Maternal heart rate.
C、 Contraction intensity.
D、 Deep tendon reflexes.

【正确答案】 B

【答案解析】Terbutaline, a beta-2 selective adrenergic agonist, is used to suppress labor by relaxing the pregnant uterus. In some cases, its beta-2 selectivity is lost, causing cardiac overstimulation. Generally, the drug is contraindicated for a client with a heart rate greater than 130 beats/minute or any cardiac arrhythmias. Therefore, the nurse would need to assess the client's heart rate.