The aim of this study was to evaluate long-term clinical follow-up and echocardiographic data on pregnant patients with mitral stenosis who underwent percutaneous mitral valvuloplasty (PMV) in our center and the development of their infants. PMV has proven to be an effective alternative to treat pregnant patients with mitral stenosis. However, long-term outcome of these patients, as well as the potential harmful effects caused by radiation on their infants, still awaits to be determined. From January 1988 to February 1999, 30 pregnant women (mean gestational duration, 24.95 +/- 5.59 weeks) underwent PMV. Twenty-three (77%) were subsequently followed by a medical interview during 5.33 +/- 3.12 years. Clinical variables such as NYHA functional class (FC), the need of a repeat PMV or surgical procedure, the presence of embolic events, and mortality rate were evaluated during follow-up. Mitral valve area, mean transmitral gradient, and the presence of mitral regurgitation were also assessed by Doppler echocardiography. Clinical data on the development of the infants were obtained from the assistant pediatricians. All patients were in NYHA FC III or IV before the procedure. During follow-up, 91% of them were in FC I and II. Two patients (9%) who had remained in FC III underwent a repeat successful PMV; no further surgery was required. There were no embolic events or death related to the procedure. Echocardiography showed an initial increase in mitral valve area from 1.14 +/- 0.22 cm(2) to 2.01 +/- 0.21 cm+/- (P < 0.0001). During long-term follow-up, it decreased to a mean of 1.75 +/- 0.24 cm(2) (P < 0. 0001). Initial transmitral valve gradient decreased from 17.73 +/- 4. 56 mm Hg to 5.91 +/- 1.80 mm Hg (P = 0.0001) and 8.95 +/- 3.58 (P = 0.002) during long-term follow-up. Twenty one children (96%), aged 4. 91 +/- 2.8 years, showed normal growth and development, and no clinical abnormalities were observed. These favorable long-term results suggests PVM to be the procedure of choice to treat pregnant women with mitral stenosis who remain in FC III or IV despite adequate medical therapy. No harmful effects due to the use of radiation were observed in the children.