In rheumatic heart disease complicating pregnancy, which valvular lesion is MOST poorly tolerated during the hemodynamic changes of the third trimester and labor?

• A Severe mitral stenosis — tachycardia in labor reduces diastolic filling time critically ✓
• B Mild mitral regurgitation — volume overload worsens as cardiac output rises
• C Moderate aortic regurgitation — afterload reduction in pregnancy is beneficial
• D Mild aortic stenosis — increases afterload against the volume-loaded pregnant heart

Explanation

Mitral stenosis is the worst-tolerated valvular lesion in pregnancy. The physiological 40–50% increase in cardiac output during pregnancy raises left atrial and pulmonary pressures across the stenotic valve. Labor tachycardia critically reduces diastolic filling time, exponentially raising trans-mitral gradient and left atrial pressure, risking acute pulmonary edema. Regurgitant lesions (MR, AR) are better tolerated in pregnancy because the reduced systemic vascular resistance of pregnancy effectively 'offloads' the regurgitant volume. Critical mitral stenosis (MVA < 1 cm²) may require percutaneous balloon mitral valvotomy in pregnancy.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.