Which fetal defect is associated with lithium exposure during pregnancy?

Which fetal defect is associated with lithium exposure during pregnancy?

• A. Ebstein's anomaly
• B. Tetralogy of Fallot
• C. Ventricular septal defect
• D. Patent ductus arteriosus

Answer: (A)

The most important concept is that lithium exposure in early pregnancy can disrupt heart development and is classically linked to Ebstein anomaly. Ebstein anomaly involves downward displacement of the tricuspid valve leaflets toward the apex, causing part of the right ventricle to become atrialized and leading to a large right atrium with tricuspid regurgitation. This defect arises during early cardiac formation when the tricuspid valve apparatus is developing, a process that can be disturbed by teratogens like lithium. That’s why Ebstein anomaly is the best answer: it is the specific fetal heart defect most consistently associated with lithium exposure in the first trimester. The other defects listed—Tetralogy of Fallot, ventricular septal defect, and patent ductus arteriosus—have different typical etiologies and are not classically linked to lithium exposure.

The most important concept is that lithium exposure in early pregnancy can disrupt heart development and is classically linked to Ebstein anomaly. Ebstein anomaly involves downward displacement of the tricuspid valve leaflets toward the apex, causing part of the right ventricle to become atrialized and leading to a large right atrium with tricuspid regurgitation. This defect arises during early cardiac formation when the tricuspid valve apparatus is developing, a process that can be disturbed by teratogens like lithium.

That’s why Ebstein anomaly is the best answer: it is the specific fetal heart defect most consistently associated with lithium exposure in the first trimester. The other defects listed—Tetralogy of Fallot, ventricular septal defect, and patent ductus arteriosus—have different typical etiologies and are not classically linked to lithium exposure.