Prevalence of Perinatal Central Nervous System Anomalies in East Azarbaijan-Iran

BACKGROUND/OBJECTIVE Central nervous system (CNS) anomalies are the most serious congenital abnormalities. Ultrasound examination is an effective and noninvasive modality for prenatal diagnosis of these anomalies. The purpose of the current study was to determine the frequency of CNS and associated abnormalities. PATIENTS AND METHODS A total of 22500 pregnant women who were referred by obstetricians/gynecologists for routine work up of pregnancy were scanned over a period of 3 years by two expert sonologists in a referral center using high resolution ultrasound unit. RESULTS After transabdominal sonographic examination of 22500 pregnant women, 112 (0.5%) fetuses were detected with CNS anomalies, some of whom had more than one anomaly. Forty-one (37%) Chiari malformations, 26 (23%) monro and aqueductal stenosis cases, 18 (16%) anencephaly cases, nine (8%) encephaloceles, seven (6%) microcephalies, five (4%) Dandywalker syndromes, two (2%) arachnoid cysts, two (2%) agenesis of corpus callosum cases, one (1%) holoprosencephaly and one (1%) schizencephaly were reported in our study. CONCLUSION According to our results, Chiari malformation and hydrocephalus were the most prevalent anomalies of CNS congenital abnormalities in East Azarbaijan, Iran. An accurate diagnosis depends upon fetal age, amniotic fluid volume, fetal position, operator experience and careful evaluation of the associated malformations, which are often present.