Fractional arm volume (AVol) and thigh volume (TVol) assessment may improve the detection and monitoring of malnourished fetuses. Use this calculator to determine the percentile and z-score for AVol and TVol measurements by entering the Menstrual Age in weeks along with the AVol and TVol measurements in mL.
Important Note: The published fractional limb volume tables in [Lee W, et al. Ultrasound Obstet Gynecol 2009;33:427-40) provide the estimated mean measurements and standard deviations for commonly used percentiles that are based on the actual number of fetuses that were studied in each menstrual age category.
By comparison, the web calculator is an online tool that is used to obtain the specific percentile and z-score that correspond to a specific menstrual age and fractional limb volume measurement. If an exact match doesn't exist for the menstrual age inputted, it is rounded-up to the nearest menstrual age available and the percentile is estimated. Hence this calculator is more precise than the published tables.