Objective: To analyze if trans-cerebellar diameter/abdominal circumference ratio (TCD/AC) and head circumference/abdominal circumference ratio (HC/AC) values remained constant throughout the gestational age (GA) and to determine the cut-off values.
Patient and Methods: In this observational prospective study, we enrolled 305 pregnant females above 20 weeks with singleton low-risk pregnancy attending outpatient clinic (OPC) or admitted to Obstetrics and Gynaecology department Mansoura University Hospitals over a period of 12 months .Using (Samsung UGEO H60&GE Logiq F6) to measure fetal biometry and assess GA including: HC(mm),TCD(mm)and AC(mm) then calculation of TCD/AC ratio [TCD was divided by AC and then multiplied by 100] and HC/AC ratio [dividing HC by AC] .
Results: Both ratios (TCD/AC and HC/AC) are relatively stable parameters that can be used for early detection of abnormal fetal growth, particularly when GA is unknown. The cut-off values of TCD/AC and HC/AC ratios to predict IUGR are 13.7 and 1.2 respectively.
Conclusion: The TCD/AC and HC/AC ratios are almost consistent and independent of gestational age. They are therefore very useful for anticipating IUGR beyond 20 weeks of gestation. TCD/AC and HC/AC ratio cut-off values are 13.7 and 1.2, respectively. Elevated any of both ratios above these cut-off values may predict IUGR at any gestational age.