To evaluate the spontaneous closure of isolated fetal ventricular septal defect (VSD) in uterus and follow-up during the first year after birth using echocardiography.

From January 2012 to June 2017, 51 cases with isolated VSD without chromosome abnormality were observed in uterus and followed-up during the first year after birth using echocardiography in People′s Hospital of Daxing District in Beijing City. The location, size, closure time of the VSD were recorded. The closure rate was calculated. The closure rate of the VSD in utero and in infant during the first year after birth were compared by Fisher exact probability method. The relation of closure rate and location and size were also analyzed (P<0.05 was significant). The comparison between groups one by one were performed by Fisher exact probability method (P<0.0167 was significant).

In 51cases, 30 had perimembranous VSD, 16 with muscular VSD and 5 with infundibular VSD. In 20 closure cases (39.2%), 9 fetuses (17.6%) were closed in utero, 11 infants (21.6%) were closed during the first year after birth. There was no significant difference between the closure rate of the VSD in utero and the closure rate of VSD in infant during the first year after birth (P=0.804). In 16 with muscular VSD, 11 cases (68.8%) were closed, in whom 4 fetuses (25.0%) were closed in utero and 7 infants (43.8%) were closed during the first year after birth. In 30 perimembranous VSD, 9 cases (30.0%) were closed, in whom 5 fetuses (16.7%) were closed in utero and 4 infants (13.3%) were closed during the first year after birth. The closure rate of muscular VSD were significant higher than that of the closure rate of perimembranous VSD and infundibular VSD (P=0.007, 0.012). There were no significant difference between the closure rate of the perimembranous VSD and infundibular VSD (P=0.297). The infundibular VSD remained unclosed in all cases. In 35 cases with VSD≤3.0 mm, 19 cases (54.3%) were closed, in whom 9 fetuses (25.7%) were closed in utero and 10 infants (28.6%) were closed during the first year after birth. There was 1 closure case (7.6%) with VSD of 3.1-5.0 mm. The closure rate of VSD≤3.0 mm were significant higher than that of the VSD of 3.1-5.0 mm and the VSD>5.0 mm (P=0.007, 0.013). There was no significant difference between the closure rate of the VSD of 3.1-5.0 mm and VSD>5.0 mm (P=1.0). The VSD>5.0 mm remained unclosed in all cases.

Isolated VSD has a high closure rate in utero and during the first year after birth. Echocardiography was a reliable method in diagnosis and follow-up of isolated VSD.