How does Nifedipine act as a tocolytic agent?

Nifedipine acts as a tocolytic agent primarily by decreasing myometrial contraction. It is a calcium channel blocker that prevents calcium ions from entering smooth muscle cells, including those in the uterus. Calcium is critical for muscle contraction; by reducing its availability in the myometrial cells, Nifedipine effectively relaxes the uterine muscle and inhibits contractions. This action is especially beneficial in the management of preterm labor, as it helps to delay delivery and allows for further fetal development while minimizing the risk of premature birth.

The other options do not accurately reflect Nifedipine’s mechanism of action in this context. While calcium availability is decreased due to its blocking effect, the primary outcome is the reduction of contractions rather than an increase in calcium. Nifedipine does not inhibit prostaglandin synthesis, which is another pathway involved in labor, nor does it have a role in enhancing testosterone production, which is unrelated to its therapeutic effects in obstetrics. Thus, the correct choice highlights the primary and relevant action of Nifedipine in managing uterine contractions.