Which medication is administered during preterm labor that requires calcium gluconate to counter its effects?

The medication administered during preterm labor that requires calcium gluconate to counter its effects is magnesium sulfate. Magnesium sulfate is commonly used as a tocolytic agent to relax the smooth muscle of the uterus and help stop preterm labor.

However, one of the significant side effects of magnesium sulfate is its potential to cause maternal neuromuscular blockade leading to respiratory depression or muscle weakness. Calcium gluconate serves as an antidote in this scenario, as it can help restore normal calcium levels and improve neuromuscular function when magnesium levels are excessively high. The administration of calcium gluconate can be life-saving in cases of magnesium toxicity, emphasizing the importance of monitoring magnesium levels in patients receiving this medication.

Other medications listed, like terbutaline, nifedipine, and indomethacin, do not have a similar requirement for calcium gluconate and do not typically lead to the necessity for such an antidote, thus distinguishing magnesium sulfate as the correct choice.