Chromosomal anomalies and additional sonographic findings in fetuses with open neural tube defects.

Objective: To evaluate the results and the necessity of chromosome analysis in fetuses prenatally detected with a neural tube defect and to determine the significance of ultrasonographic evaluation for the identification of underlying or accompanying chromosomal anomalies.

Methods: Ninety fetuses that underwent prenatal and/or postnatal chromosome analysis after being diagnosed with open neural tube defects (NTD) between the years 2006 and 2010 in the Department of Obstetrics and Gynecology at Ondokuz Mayis University School of Medicine were included in this study. Detailed fetal ultrasonography was performed in all cases in order to investigate any additional anomalies. Karyotype was determined in the prenatal period by amniocentesis in 72 (80%) of the 90 fetuses, and by cordocentesis in 5 (5.5%). In 13 (13.3%) fetuses, karyotype was determined in the postnatal period by blood sampling.

Results: Fourteen (15.5%) of the 90 fetuses were diagnosed with acrania/anencephaly, 14 (15.5%) with encephalocele, 2 (2.2%) with iniencephaly, 60 (66.6%) with open spina bifida. None of the 90 fetuses with open NTD who had undergone chromosome analysis was diagnosed with chromosomal anomalies. None of the 19 (21.1%) fetuses diagnosed with additional ultrasound findings had a chromosomal abnormality, either. Seventy-one (78.9%) fetuses having sonograhically isolated NTD were also isolated in postmortem examination.

Conclusion: In fetuses with open NTD, we could not find the chromosomal anomaly rate as high as reported in previous literature. The necessity of fetal karyotyping should be questioned especially in isolated cases.