Tocolytic of choice in pregnancy with hea disease (OBG)
**Core Concept**
The question is testing the knowledge of tocolytic agents, which are medications used to suppress premature labor in pregnant women. The underlying principle is to identify the most suitable tocolytic agent for a pregnant woman with heart disease, considering the potential risks and benefits of each option.
**Why the Correct Answer is Right**
Beta-2 agonists, such as ritodrine, are often used as tocolytics to suppress premature labor. However, in a pregnant woman with heart disease, a more cautious approach is required. Magnesium sulfate is a commonly used tocolytic agent in this scenario, as it has a more favorable cardiovascular profile and can also provide neuroprotection for the fetus. Its mechanism of action involves inhibiting calcium entry into smooth muscle cells, leading to relaxation of uterine muscle and suppression of contractions.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because beta-2 agonists, such as ritodrine, can exacerbate heart disease by increasing myocardial oxygen demand and potentially leading to cardiac ischemia.
**Option B:** This option is incorrect because prostaglandin synthetase inhibitors, such as indomethacin, can have adverse effects on fetal circulation and are generally contraindicated in pregnancy with heart disease.
**Option C:** This option is incorrect because calcium channel blockers, such as nifedipine, can also have adverse effects on fetal circulation and may not be suitable for a pregnant woman with heart disease.
**Clinical Pearl / High-Yield Fact**
When managing a pregnant woman with heart disease in premature labor, it is essential to carefully balance the risks and benefits of tocolytic agents and consider alternative options, such as magnesium sulfate, to minimize the risk of adverse cardiovascular events.
**Correct Answer:** B. Magnesium sulfate