Efficacy of Transcerebellar to Abdominal Circumference versus Head Circumference to Abdominal Circumference Ratio in Predicting Asymmetrical Intrauterine Growth Restriction

Abstract

Background: Fetal growth restriction (FGR) is when a fetus is not able to achieve its genetic growth potential. The high incidence of FGR in the general obstetric population and its low recognition together lead to increased perinatal morbidity and mortality, and its early detection is useful in deciding the frequency of antenatal surveillance and optimizing the time of delivery to improve the neonatal outcome. The transverse cerebellar diameter/abdominal circumference (TCD/AC) ratio is a gestational age-independent parameter, which may be helpful in the early detection of FGR. Objectives: To compare the accuracy of transcerebellar to AC with head circumference (HC) to AC in predicting asymmetrical FGR after 20 weeks of gestation and to determine the significance of TCD and TCD/AC relationship in predicting fetal outcome as expressed by perinatal morbidity and mortality. Study Design: A prospective observational study. Materials and Methods: This prospective observational study was conducted in the Postgraduate Department of Obstetrics and Gynaecology. A total of 300 patients were taken and divided into two groups: Group A (patients of suspected FGR clinically) and Group B (healthy women with morphologically normal fetuses) in the age group of 18–35 years. Subjects with singleton, nonanomalous pregnancy, reliable dates, favorable lie to visualize posterior fossa, and gestation of 20 weeks or more, were taken from the said age group and followed for maternal and neonatal outcome. Results: The difference in TCD/AC ratio between patients with FGR (14.8 ± standard deviation [SD]) and without FGR (13.10 ± SD) is statistically significant with a P < 0.0001 with good sensitivity (93%), specificity (94%), and diagnostic accuracy (93.66%) in predicting asymmetrical FGR when compared to HC/AC ratio with sensitivity 83%, specificity 93%, and diagnostic accuracy of 89.66%. Conclusion: The TCD/AC ratio is constant throughout pregnancy and is increased in FGR compared to normal pregnancy and can be used as a screening test to diagnose FGR.

Keywords

• fetal growth restriction
• head circumference to abdominal circumference ratio
• transcerebellar to abdominal circumference ratio