A 30-year-old woman with severe aortic stenosis presents at 38 weeks of gestation of her first pregnancy. She was asymptomatic at conception, but developed mild exertional dyspnea during the second trimester. The dyspnea has slowly worsened since. No other symptoms are present. She was otherwise normal when evaluated at 36 weeks. Her surgical history is unremarkable. She is not on any medications currently. There is no history of allergies.