Demographic factors and associated anomalies in fetuses with neural tube defects

The aim of this study was to identify the types of abnormalities associated with neural tube defects (NTDs) and the magnitude of the risk for their expression under the influence of the following factors: maternal age >35 years, consanguinity and season of conception. One hundred and fifty fetuses were autopsied during the period 2006-2009 at the Center for Maternity and Neonatology, Tunisia. A mother's age of >35 years increases the probability of intrauterine growth retardation by two-fold [odds ratio (OR) 2.043, confidence interval (CI) 0.880-4.741]. Consanguinity increases the relative risk for abnormalities in the facial shape (OR 3.031, CI 1.279-7.183) and adrenal hypoplasia (OR=2.787, CI 1.140-6.814). The autumn-winter period of conception increases the relative risk for the expression of cleft palate by more than nine times (OR 9.035, CI 1.161-70.258) and by about three times for abnormalities of the excretory tract (OR 2.935, CI 0.954-9.141). The prenatal ultrasound diagnosis of NTDs with risk factors such as maternal age >35 years, consanguinity and conception during the autumn-winter period should be targeted to the search for lower-than-normal fetal weight and abnormalities of the excretory tract and the adrenal glands. The head should be examined with special care for deviations in the cranial perimeter and cleft palate.