Question

Assertion (A): All newborns should be screened for hypothyroidism at birth.

Reason (R): Treatment at birth for hypothyroidism can assure normal mental development.

• A. Both A and R are true and R is the correct explanation of A.
• B. Both A and R are true but R is NOT the correct explanation of A.
• C. A is true but R is false.
• D. A is false but R is true.

Hint:

Congenital hypothyroidism looks normal at birth but causes irreversible brain damage if treatment is delayed.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
We need to see why newborn screening for hypothyroidism is recommended, and whether the stated reason really explains that recommendation.

Step 2: Key Concept:
Congenital hypothyroidism is one of the most common preventable causes of intellectual disability in children. The baby looks almost normal at birth, so the condition is easy to miss on a routine clinical check. Thyroid hormone is needed in the first weeks of life for normal brain growth, so a delay in starting treatment causes permanent, irreversible loss of mental development.

Step 3: Detailed Explanation:
Assertion (A) states that all newborns should be screened for hypothyroidism at birth. This is true and is part of standard newborn screening programs, done through a simple heel-prick blood test for TSH soon after birth.
Reason (R) states that treatment started at birth can assure normal mental development. This is also true: starting thyroid hormone replacement within the first two to four weeks of life prevents the brain damage that untreated congenital hypothyroidism would otherwise cause.
Since the whole point of screening at birth is to catch the disease early enough to start treatment before brain damage sets in, R is exactly the reason why A is recommended.

Step 4: Final Answer:
Both statements are true and R correctly explains A.