In a lady of 32 weeks pregnancy injection dexamethasone is to given to prevent:
First, I need to recall the main indications for corticosteroids in pregnancy. The most common one is for preterm labor to accelerate fetal lung maturity. Dexamethasone is a synthetic glucocorticoid that crosses the placenta and stimulates the production of surfactant in the fetal lungs. Surfactant reduces surface tension in the alveoli, preventing collapse and reducing the risk of respiratory distress syndrome (RDS) in preterm infants. The standard regimen is usually given in two doses 12 hours apart, starting 24-48 hours before delivery if preterm birth is anticipated.
Now, the options might include things like preventing maternal preeclampsia, preventing gestational diabetes, or treating an infection. But the correct answer here would be related to fetal lung maturity. Let me think of other possibilities. Sometimes, corticosteroids are used in other contexts, like for inflammation or autoimmune conditions, but in the context of a 32-week pregnancy, the primary indication is preterm labor.
Wait, the options are A to D, but the user hasn't listed them. However, the correct answer is probably about preventing RDS. So the core concept is the use of antenatal corticosteroids to accelerate fetal lung maturation. The correct answer would be option C or D, depending on the options given. But since the user hasn't provided the options, I need to state the correct answer as per the standard knowledge.
So, the core concept is that dexamethasone is used in preterm labor to induce surfactant production. The correct answer is to prevent RDS. The wrong options would be other conditions like preeclampsia, gestational diabetes, or maternal infections. The clinical pearl here is that antenatal corticosteroids are a key intervention to improve outcomes in preterm births. The correct answer is likely option C or D, but since the options aren't provided, I'll proceed with the explanation based on standard knowledge.
**Core Concept**
Antenatal corticosteroids like dexamethasone are administered to pregnant women at risk of preterm delivery (before 34 weeks) to accelerate fetal lung maturation. This reduces neonatal respiratory distress syndrome (RDS) by stimulating surfactant production in type II alveolar cells.
**Why the Correct Answer is Right**
Dexamethasone crosses the placenta and activates fetal adrenal and lung receptors. It induces the expression of surfactant proteins (SP-A, SP-B, SP-C) and phospholipid synthesis, critical for reducing alveolar surface tension. Administration 24–48 hours before delivery reduces RDS incidence by 50–70% in preterm infants. This is a cornerstone of management in threatened preterm labor.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect if it refers to maternal hypertension management; corticosteroids do not prevent preeclampsia.
**Option B:** Incorrect if it refers to gestational diabetes; steroids may transiently increase maternal glucose but are not used to prevent