Correlation Between Fetal Anterior-Posterior Thigh Diameters and Routine Ultrasound Parameters in Determining Gestational Age

Determining the exact gestational age can prevent many complications and unpleasant consequences of pregnancy such as fetal growth retardation, premature birth and prenatal mortality.

This study aimed to measure fetal anterior-posterior thigh diameter, as a new method for determining gestational age, and to compare it with routine ultrasound parameters (biparietal diameter, femur length).

In this study, 105 pregnant women with gestational age 18 - 28 weeks who presented to Kermanshah Imam Reza Hospital were recruited. Gestational age was determined based on last menstrual period (LMP). Then, ultrasound was performed to measure gestational age with anterior-posterior thigh diameter and other routine parameters (biparietal diameter, femur length). Finally, the results were evaluated with KS and Spearman’s correlation coefficient in SPSS version 22. Significance level was set as 0.05.

A significant correlation existed between estimation of gestational age based on ultrasound parameters and LMP, and between anterior-posterior thigh diameter and routine ultrasound parameters (P < 0.05). Hence, anterior-posterior thigh diameter is as good as biparietal diameter and femur length for estimation of gestational age.

According to the results, using anterior-posterior thigh diameter can be a reliable method in estimation of gestational age in the second trimester in addition to routine parameters.