Transcerebellar Diameter in Normal and Fetal Growth-Restricted Pregnancies: A Comparative Sonographic Study

Abstract

Background: Accurate gestational age (GA) assessment is important for antenatal surveillance and obstetric decision-making. Conventional fetal biometric measurements may be affected by altered growth patterns in fetal growth restriction (FGR). Transcerebellar diameter (TCD) has been proposed as an additional sonographic parameter because cerebellar growth may be relatively preserved in some growth-restricted pregnancies. This study compared TCD measurements between normal and intrauterine growth-restricted (IUGR) pregnancies and examined the relationship of TCD with amniotic fluid index (AFI). Methods: A comparative study was conducted over four months at the University Ultrasound Clinic, Green Town, Lahore. A convenience sample of 100 pregnant women in the second trimester was included. Ultrasound examinations were performed using a Toshiba Xario XG system with a 3–5 MHz convex probe. Participants were classified into non-IUGR and IUGR groups (50 in each group). Descriptive statistics, one-way analysis of variance (ANOVA), and correlation analyses were reported. Results: Participants had a mean age of 29.54 years (SD = 2.47) and a mean GA of 21.00 weeks (SD = 1.97). Mean AFI was 10.62 cm (SD = 1.82), and mean TCD was 21.00 mm (SD = 1.97). Mean TCD was higher in the non-IUGR group than in the IUGR group (21.46 ± 1.70 vs. 20.54 ± 2.13 mm; F(1, 98) = 5.684, p = .019). TCD showed a moderate positive correlation with AFI (r = .4065, 95% CI [.2284, .5584], p < .0001) and a weak negative correlation with IUGR status (r = −.2341, 95% CI [−.4116, −.0395], p = .019). Conclusion: TCD measurements differed significantly between the non-IUGR and IUGR groups and were positively associated with AFI in this second-trimester sample. These findings suggest that TCD may provide complementary information during fetal assessment. The study does not, however, establish diagnostic accuracy or independently validate TCD-based gestational dating; larger studies using a clearly defined reference standard and standardized FGR criteria are required.