A women has had 2 previous anencephalic babies, risk of having a third one is:
**Core Concept**
The underlying principle being tested is the risk of recurrence of a congenital anomaly, specifically anencephaly, which is a type of **neural tube defect (NTD)**. Anencephaly is a severe congenital anomaly where a major portion of the brain, skull, and scalp are absent. The risk of recurrence is an important aspect of **genetic counseling**.
**Why the Correct Answer is Right**
Given that the woman has had two previous anencephalic babies, this indicates a possible genetic or environmental predisposition to **NTDs**. The risk of recurrence in such cases is higher than in the general population, particularly if there is a familial component or if the couple has not taken preventive measures such as **folic acid supplementation**, which is known to reduce the risk of **NTDs**.
**Why Each Wrong Option is Incorrect**
**Option A:** This option would be incorrect because it underestimates the risk associated with a history of two affected children.
**Option B:** This option might seem plausible but does not accurately reflect the increased risk associated with two previous anencephalic babies.
**Option D:** This option overestimates the risk and does not align with the empirical data on recurrence risks for **NTDs**.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that the risk of recurrence for **NTDs** like anencephaly is significantly higher in families with a history of such defects, emphasizing the importance of **folic acid supplementation** before and during early pregnancy to mitigate this risk.
**Correct Answer:** C. 3-5%