Hypertrophic cardiomyopathy (HCM) is a rare, often familial condition, which may be complicated by syncope, atrial or ventricular arrhythmias and episodes of cardiac failure. This genetic disease affects young people and may be observed in women wishing for a pregnancy. The duration and outcome of such pregnancies has not been extensively studied. The authors undertook a retrospective study by questionnaire to compare the pregnancies of 41 women with HCM, a total of 150 pregnancies, with those of 39 unaffected women from the same families: a total of 132 pregnancies. None of the women died, there were no hospital admission for cardiac causes and there was no aggravation of functional status (31% of women with HCM had symptoms before pregnancy compared with 27% during pregnancy). The foetal prognosis was good with no increase in prematurity or neonatal crises. Only the women with symptoms before pregnancy had an increased risk of foetal prematurity compared with healthy women (18% versus 5%). These results indicate the good tolerance of pregnancy of women with HCM and should lead to a revision of systematic medical contra-indication of pregnancy in these patients.