Outcomes of prenatally diagnosed fetal ventricular septal defects: a seven-year single-center experience

To evaluate the prenatal course and outcomes of fetuses diagnosed with ventricular septal defect (VSD) during second-trimester detailed ultrasound examination and to assess factors associated with spontaneous prenatal closure. This retrospective cohort study was conducted at a tertiary referral center between January 2014 and January 2021. Fifty-seven fetuses with prenatally diagnosed VSD were identified among 12,632 pregnancies undergoing detailed fetal anomaly screening. Demographic characteristics, gestational age at diagnosis, defect type, size, location, associated anomalies, genetic findings, and prenatal closure status were recorded. Atrioventricular septal defects and multiple pregnancies were excluded. Among 12,632 pregnancies evaluated during the study period, 57 fetuses (0.4%) were diagnosed with VSD. Perimembranous VSD was detected in 8 cases (14.1%), whereas muscular VSD was identified in 49 cases (85.9%). The defect measured less than 3 mm in 46 fetuses (80.7%). Spontaneous prenatal closure occurred in 34 of 57 cases (59.6%), including 32 of 49 muscular VSDs (65.3%) and 2 of 8 perimembranous VSDs (25%). Chromosomal abnormalities were identified in two fetuses, both of whom had inlet perimembranous VSDs and associated structural anomalies. Most prenatally diagnosed VSDs were small muscular defects. Spontaneous prenatal closure was more common in muscular VSDs and defects measuring less than 3 mm, whereas perimembranous and inlet defects showed lower closure rates. These findings may contribute to prenatal counseling and follow-up planning for pregnancies complicated by fetal VSD. Given the limited sample size, the small perimembranous subgroup, and the absence of comprehensive genetic testing in all cases, these results should be interpreted with caution.