Which medication is contraindicated for a woman with poorly controlled diabetes during tocolysis?

Terbutaline is contraindicated for a woman with poorly controlled diabetes during tocolysis due to its potential adverse effects on glycemic control. As a beta-agonist, terbutaline can cause an increase in blood glucose levels, which may exacerbate hyperglycemia in a patient already struggling to maintain stable glucose levels. This is particularly concerning in the context of pregnancy, as poorly controlled diabetes can lead to significant maternal and fetal complications, including macrosomia, preterm birth, and increased risk of neonatal hypoglycemia.

In contrast, other medications listed, such as nifedipine, magnesium sulfate, and indomethacin, do not have the same direct impact on blood glucose levels and may be safer options for managing preterm labor in patients with diabetes. Nifedipine is a calcium channel blocker that helps to relax the uterus without affecting blood sugar significantly. Magnesium sulfate is typically used for both tocolysis and neuroprotection for the fetus, and indomethacin is a nonsteroidal anti-inflammatory drug that acts as a tocolytic but also does not pose the same risk to glycemic control as terbutaline does.