Final answer:
The nurse should monitor the client for hypotonic uterine contractions as a side effect of terbutaline (Brethine) used to halt preterm labor.
Step-by-step explanation:
The nurse should monitor the client for hypotonic uterine contractions as a side effect of terbutaline (Brethine) used to halt preterm labor. Terbutaline is a medication that acts as a smooth muscle relaxant, and while it helps to relax smooth muscles in the lungs, it can also relax the smooth muscles of the uterus. As a result, the uterine contractions may become weak and less effective, which can delay labor progress and potentially increase the risk for complications.