Investigating sex-based disparities in fetal spinal neural tube defects: an observational 12 Years-long study

AIM: This study investigates the impact of fetal sex on the prenatal diagnosis of spina bifida, comparing male to female ratio in spinal neural tube defects (NTD), maternal, obstetric and ultrasound characteristics and perinatal outcomes. METHODS: This was a retrospective, observational cohort study conducted at a single tertiary referral center, from 2011 to 2022. The study included 247 fetuses diagnosed prenatally with spinal NTDs. Maternal characteristics, ultrasound findings, genetic testing results, and perinatal outcomes were analyzed. Fetal sex was determined by ultrasound, at birth, or through genetic testing. Logistic regression and log-linear models were used to estimate odds ratios (OR) and ratios of means with 95% confidence intervals (CI). RESULTS: Fetal sex was determined in 245 cases, comprising 122 male and 123 female fetuses, resulting in a balanced male-to-female ratio, (OR 0.99, 95%CI 0.77-1.27). Maternal characteristics were similar between groups. Overall, no sex-related differences were observed in key prenatal ultrasound parameters, including the presence of associated anomalies, anatomical level, motor level, or ventricular size. Although male fetuses were more frequently diagnosed in the first trimester, this did not correspond to differences in lesion severity. Perinatal outcomes, including termination of pregnancy, stillbirth, neonatal death, and eligibility for prenatal repair, were comparable between sexes. CONCLUSION: Among fetuses diagnosed prenatally with spinal NTD, the male-to-female ratio was 1:1. No significant sex-based differences were found in maternal characteristics, ultrasound findings, or perinatal outcomes. These results suggest that, within this clinical setting, fetal sex does not influence the prenatal phenotype or early clinical course of spina bifida.