Drug given to reduce uterine contractions during preterm labour with least side effects :
**Core Concept**
The management of preterm labor involves the use of tocolytic agents to reduce uterine contractions and allow for fetal maturation. The ideal tocolytic agent should be effective in reducing contractions while minimizing side effects.
**Why the Correct Answer is Right**
Atosiban, a selective oxytocin receptor antagonist, is used to reduce uterine contractions during preterm labor. It works by competitively inhibiting the action of oxytocin at the oxytocin receptor, thereby reducing uterine contractions. Atosiban has a favorable side effect profile compared to other tocolytic agents, making it a preferred choice for the treatment of preterm labor.
**Why Each Wrong Option is Incorrect**
* **Option A:** Ritodrine is a beta-2 adrenergic agonist that can cause tremors, tachycardia, and hypertension as side effects. Its use is associated with an increased risk of pulmonary edema.
* **Option B:** Nifedipine is a calcium channel blocker that can cause hypotension, headache, and flushing as side effects. It may also cause reflex tachycardia.
* **Option D:** Magnesium sulfate can cause respiratory depression, cardiac arrest, and neuromuscular blockade as side effects. It is also associated with an increased risk of neonatal hypotonia and respiratory depression.
**Clinical Pearl / High-Yield Fact**
Atosiban is a tocolytic agent that works by inhibiting the action of oxytocin at the oxytocin receptor, making it a preferred choice for the treatment of preterm labor due to its favorable side effect profile.
**Correct Answer:** C. Atosiban