Idiopathic hypertrophic subaortic stenosis in pregnancy.

The coexistence of pregnancy and idiopathic hypertrophic subaortic stenosis is a potentially dangerous combination. We report a 23-year-old white woman with idiopathic hypertrophic subaortic stenosis and pregnancy who presented with severe symptoms (Class IV) and modest outflow obstruction associated with marked mitral regurgitation. After delivery, the evidence for significant mitral regurgitation regressed, while the outflow obstruction seemed unchanged. However, she returned to Functional Class II. We review the mechanisms by which pregnancy and labor may alter the hemodynamics of idiopathic hypertrophic subaortic stenosis and we discuss recommendations for the management of these patients during pregnancy, labor, and the immediate postpartum period. We conclude that despite increasing symptoms, most women with diopathic hypertrophic subaortic stenosis can tolerate pregnancy and a vaginal delivery.