Neural Tube Defects: Distribution and Associated Anomalies Diagnosed by Prenatal Ultrasonography in Iranian Fetuses

Objectives: The current study aimed at providing detailed information about the distribution, associated anomalies, and syndromes in Iranian fetuses with neural tube defects (NTDs)
Methods: The current study was conducted in Yas Females’ referral and teaching hospital in 18 months from 2014 to 2016. All fetuses with a prenatally detected neural tube defect were included in the study. Neural tube defect characterization, gestational age, maternal reproductive factors, maternal risk factors, and associated anomalies were recorded.
Results: Neural tube abnormalities were identified prenatally in 80 fetuses: 40 cases of ex/anencephaly, 22 cases of spina bifida, 13 cases of cephalocele and 5 cases of anencephaly /craniorachischisis. All the cases were detected before 21st week of gestation and 92.5% of the ex/anencephaly cases were diagnosed in the 1st trimester. Moreover, 40% of the open spina bifida cases in the current study were myelocele, while 75% of them referred only due to abnormal cranial findings. Incomplete consumption of folate was the most common associated risk factor (45%). Associated anomalies were recorded in 53 (66%) fetuses, with more prevalence in the fetuses with spina bifida (90%). Among the associated anomalies, central nervous system (CNS) anomalies were the most common type (26.26%). Chiari II was found in all the cases of open spina bifida and the ventriculomegaly rate was 30% in this group. Extremities anomalies and spine deformities were the 2nd and 3rd common associated findings, respectively. Limb-body-wall complex/amniotic band syndrome was the most common identified associated syndrome (6%).
Conclusions: Results of the current study confirmed the high prevalence of associated anomalies in neural tube defect cases and revealed the capability of detailed sonography to detect and define such abnormalities