Lithium is used in a pregnant woman. Which of the following congenital anomaly occurs in foetus:
## **Core Concept**
Lithium is a medication commonly used to treat bipolar disorder. Its use during pregnancy is associated with an increased risk of congenital anomalies in the fetus. The most commonly reported congenital anomaly associated with lithium exposure is related to cardiac development.
## **Why the Correct Answer is Right**
The correct answer, **Ebstein's anomaly**, is a congenital heart defect characterized by the abnormal formation of the tricuspid valve and the right ventricle. Lithium use during pregnancy has been specifically linked to an increased risk of Ebstein's anomaly, although the absolute risk remains low. The mechanism by which lithium causes this anomaly is not fully understood, but it is thought to involve effects on cardiac development during embryogenesis.
## **Why Each Wrong Option is Incorrect**
- **Option A:** While lithium may have effects on fetal development, **Polycystic kidney disease** is not specifically associated with lithium use during pregnancy. Polycystic kidney disease is a genetic disorder characterized by the growth of numerous cysts in the kidneys.
- **Option B:** **Cleft palate** is a congenital deformity that can result from various factors, including genetic predisposition and environmental exposures. However, it is not specifically linked to lithium use in pregnancy as a primary concern.
- **Option D:** **Down syndrome**, also known as trisomy 21, is a genetic disorder caused by the presence of an extra copy of chromosome 21. It is not directly associated with lithium exposure during pregnancy.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that while lithium is associated with an increased risk of Ebstein's anomaly, the overall risk is still low. The absolute risk of Ebstein's anomaly with lithium exposure is estimated to be around 1 in 1,000 to 1 in 2,000. However, lithium is often considered for use in pregnant women with bipolar disorder due to the significant risks associated with untreated psychiatric illness.
## **Correct Answer:** . Ebstein's anomaly