A 26-year-old with known rheumatic mitral stenosis (valve area 0.9 cm²) becomes pregnant. She is in New York Heart Association (NYHA) Class II. Which statement regarding management of mitral stenosis in pregnancy is most accurate?

• A Percutaneous balloon mitral valvotomy (PBMV) is absolutely contraindicated during pregnancy
• B Anticoagulation with LMWH is unnecessary in sinus rhythm with moderate MS during pregnancy
• C Delivery should always be by cesarean section to avoid haemodynamic stress of labour
• D Heart rate control with beta-blockers is crucial to maintain adequate diastolic filling time; PBMV can be performed in the second trimester if symptoms worsen despite medical therapy ✓

Explanation

In mitral stenosis, a fixed valve area creates pressure-dependent flow — tachycardia (shortened diastole) is the most dangerous physiological perturbation in pregnancy because increased heart rate from physiological hypervolaemia reduces diastolic filling time, raising left atrial pressure and precipitating pulmonary oedema. Beta-blockers (metoprolol) are the mainstay to maintain heart rate < 90/min. PBMV during pregnancy is indicated for symptomatic severe MS (valve area < 1.0 cm²) with NYHA Class III/IV refractory to medical management — it is preferably performed in the second trimester (organogenesis complete, uterus not yet impeding access). Anticoagulation is recommended for MS with atrial fibrillation or prior thromboembolism. Vaginal delivery with epidural anaesthesia is preferred to avoid surgical stress of cesarean.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.