Imaging the Pregnant Woman with Congenital Heart Disease: From Anatomy to Cardiovascular Reserve

Pregnancy in women with adult congenital heart disease is increasingly encountered in clinical practice, but the relevant imaging question is not simply which congenital lesion is present. The more useful question is whether the repaired, palliated, or native circulation has sufficient cardiovascular reserve to accommodate pregnancy and whether this reserve changes over time. This Viewpoint proposes a practical, phenotype-based approach to cardiovascular imaging from pre-pregnancy assessment through gestation, delivery, and the postpartum period. Transthoracic echocardiography remains the first-line technique and should define ventricular function, valve disease, residual obstruction or shunting, pulmonary haemodynamics, and aortic dimensions when relevant. Cardiovascular magnetic resonance is most useful when echocardiography cannot adequately quantify ventricular volumes, complex anatomy, great vessels, or Fontan pathways. Importantly, ionizing radiation should not be avoided when imaging is clinically necessary: computed tomography, nuclear medicine, and catheter-based imaging can be used when the expected maternal benefit outweighs radiation-related risk and exposure is optimized. Current outcome studies identify ventricular dysfunction, high-risk valve disease or outflow obstruction, pulmonary hypertension, aortopathy, cyanosis, and complex circulations such as the systemic right ventricle and Fontan pathway as important features associated with pregnancy risk. However, evidence linking changes on serial imaging to specific management thresholds remains limited. The next step for cardio-obstetric imaging is therefore not more imaging, but better validated imaging, with standardized longitudinal measurements, pregnancy-specific reference ranges, and prospective evidence showing when an imaging change should alter care.