Isolated Narrow Cavum Septum Pellucidum in Fetuses

Objectives This retrospective study aimed to describe the outcome of a cohort of fetuses with isolated narrow cavum septum pellucidum (CSP), as identified by ultrasound (US) during the second or third trimester. Methods We reviewed the records of all patients referred for CSP abnormalities and identified those fetuses diagnosed with isolated narrow width of CSP (<3 mm) on US. Results The study population comprised 79 patients with isolated narrow CSP. 36 (36/79, 45.6%) underwent MRI, and a normal corpus callosum was observed in 34 (34/36, 94.4%) cases. Partial agenesis of the corpus callosum was diagnosed in the remaining two (2/36, 5.6%) cases. In addition, no pathological findings were reported in non‐invasive prenatal testing NIPT (n = 47) and in amniocentesis (n = 11). A total of 33 (33/79, 41.8%) pregnant women gave birth at our institution, with an average Apgar score of 8–9. Neurodevelopmental outcome was available for 24 cases at a mean age of 31.6 ± 18.4 months, all of which were normal. Conclusions Almost all fetuses with isolated narrow CSP have a normal corpus callosum, and the neurodevelopmental outcome of these fetuses is generally good. Thus, isolated narrow CSP in the fetus can be considered a variation of normal development.