In the second trimester, how should CHD be monitored?

• A. One-time screening at 20 weeks.
• B. Serial targeted fetal echocardiography to assess progression, valve function, and ductal-dependent lesions, with counseling and planning.
• C. MRI-only follow-up.
• D. No follow-up unless symptoms after birth.

Answer: (B)

Serial targeted fetal echocardiography is essential in the second trimester because congenital heart disease can evolve as the fetus grows and some lesions rely on ductal-dependent circulation after birth. Repeated, focused exams allow us to track anatomy and function over time, monitor valve performance, assess ventricular function, and detect changes such as increasing regurgitation, evolving obstruction, or progression toward or away from hemodynamic instability. This ongoing assessment informs counseling and perinatal planning, including arranging delivery at a tertiary center with pediatric cardiology and surgical capabilities and preparing to manage ductus-dependent lesions after birth (for example, having prostaglandin E1 ready if needed).

A one-time screen at 20 weeks misses possible progression, MRI-only follow-up lacks the real-time functional information provided by echocardiography, and waiting for postnatal symptoms neglects the critical window when intervention planning and stabilization are most effective.