Results:Of the 76 cases with m-VSD, 1 fetus died after birth and 31 cases were lost to follow-up after birth. Thus, a total of 44 fetuses reached their first year of postnatal life, and these cases were available for analysis. Three (6.8%) of 44 defects closed spontaneously in utero, 33 (75%) closed within 1 year, and 8 (18.2%) remained patent. Overall, spontaneous closure occurred more frequently in the apical defects, but no significant difference was found for spontaneous closure between the mid-muscular and apical defects (p>0.05). Also, 83.8% (36 of 44) of defects ≤3 mm closed during gestation or the first year of life. Key words: Isolated, muscular ventricular septal defect, spontaneous closure Received: 15 January, 2014 Accepted: 11 March, 2014 Natural history of prenatal isolated muscular ventricular septal defects
Conclusion: