Gestational age estimation using fetal transcerebellar diameter and choroid plexus length compared with conventional biometric parameters in healthy Nigerian women: A longitudinal study

ABSTRACT Background: The decline in the accuracy of biparietal diameter (BPD), head circumference (HC), femur length (FL), and abdominal circumference (AC) as gestation advances has complicated the distinction between pre- and postterm pregnancies. This study evaluated the correlation between the gestational age (GA) obtained from transcerebellar diameter (TCD) and choroid plexus length (CPL) with the GA obtained using crown-rump length (CRL) and compared the GA obtained from TCD and CPL with the average GA from the conventional biometric parameters. Methods: This longitudinal prospective study was conducted from December 2023 to May 2025 on 204 pregnant women between 14 and 40 weeks of gestation in a private hospital in Nigeria. A Mindray DC-7 ultrasound system, with a 3.5 MHz curvilinear probe, was used. TCD and CPL were measured using the suboccipitobregmatic and transventricular planes, respectively. Data were analyzed using paired sample t- tests, with statistical significance set at P < 0.05. Results: In the second trimester, there were no statistically significant differences between CRL and individual parameters: BPD, HC, FL, AC, TCD, and CPL ( P > 0.05). However, combined TCD and CPL differ significantly from CRL. In the third trimester, significant differences were found between BPD, HC, and AC with CRL ( P < 0.05), while FL, TCD, and CPL remained consistent with CRL ( P > 0.05). Conclusion: TCD and CPL are reliable alternatives to conventional biometric parameters for GA estimation in the second and third trimesters. However, CPL exhibited some variation in late pregnancy and should be combined with the TCD for better accuracy.