Fetal cavum septum pellucidum nomogram and its relationship with fetal Doppler: a prospective study of a Turkish population

Abstract

Aim: Septum pellucidum is a thin membrane with right and left leaves, and cavum septum pellucidum (CSP) is formed in the intermembrane region. This study investigates CSP nomogram dimensions for all trimesters in the Turkish population. In addition, the relationship between fetal Doppler flow and CSP size was investigated in this study.Material and Method: This study was designed as a prospective cohort between 2019-2020. Pregnant women between 19-42 weeks who were followed up at University of Health Sciences Tepecik Training and Research Hospital, Department of Obstetrics and Gynecology were included in the study.Results: A total of 517 fetuses meeting our criteria were included in this prospective study. In the second trimester (19-28 weeks) CSP width (4.12±0.88 vs. 4.91±1.42, p<0.001) and length (7.95±1.04 vs. 9.48±2.19, p<0.001) were significantly higher than in the third trimester (28-42 weeks). While the mean CSP width increased up to 32nd weeks, there was no clear increase-decrease pattern between 32nd-38th weeks, and it was observed to decrease after 38th weeks. The mean CSP length increased up to 29th weeks, while there was no clear increase-decrease pattern between 29th-38th weeks, but decreased after 38th weeks. While a significant correlation was observed between gestational week and CSP width (r=0.118, p=0.010), there was no significant correlation between CSP length (r=0.086, p=0.062). A significant correlation was observed between biparietal diameter (BPD) and CSP width (r=0.180, p<0.001) and length (r=0.202, p<0.001), but not with head circumference (HC). There was a significant correlation between middle cerebral artery (MCA) systolic/diastolic ratio (S/D) (r=0.185, p<0.001), pulsatility index (PI) (r=0.210, p<0.001) and resistive index (RI) (r=0.233, p<0.001) and CSP length, but not with CSP width.Conclusion: Turkish population fetal CSP nomogram is presented in this study. Fetal middle cerebral artery Doppler measurements (S/D, PI, and RI) showing cerebral blood flow correlate with CSP length, but not with CSP width. There was no correlation between fetal umbilical artery Doppler measurements and CSP sizes. The results pave the way for population-based studies with much larger samples.