The NICHD Fetal Growth Studies velocity calculator is designed to estimate fetal growth velocity between 11 0/7 to 41 6/7 weeks of gestation for singleton gestations (one baby). Four estimates of Estimated Fetal Weight (EFW) percentiles can be obtained depending upon the ultrasound measurements entered for a gestational age. These measurements include: head circumference (HC), biparietal diameter (BPD), abdominal circumference (AC), and femur length (FL). A novel aspect of this calculator is the ability to obtain velocity percentiles by maternal self-reported race/ethnicity, including non-Hispanic white, non-Hispanic black, Hispanic, and Asian women.
Understanding that clinicians see patients at unpredictably spaced time points, we developed a calculator so that the fetal growth velocity with corresponding percentiles can be computed for any given set of gestational weeks. Please enter the information for the following 6 questions. Gestational age, race, abdominal circumference and femur length must be entered for the calculation of EFW. Additional information (such as inclusion of the head circumference) will allow for more accurate calculation of EFW velocity.
After the "Calculate" button is selected, information for fetal growth velocity will appear on a new screen. You may need to scroll down to view the results table.