NIH Websites Are Changing

Get the Latest Updates and FAQs on the transition

Per Executive Order 14434 , federal agencies are now using "Super Intelligence" (SI) in place of "Artificial Intelligence" (AI). You may see both terms across NIH content during this transition.

Fetal Growth Calculator - Definitions

Definitions

  • Gestational Age:
    Age of the pregnancy, in completed weeks and days   
  • Biparietal Diameter (BPD):
    Distance between the two parietal bones of the fetal skull (outer to inner), in millimeters   
  • Head Circumference:
    Measurement of the fetal head at its widest, in millimeters   
  • Abdominal Circumference: Measurement of the fetal abdomen, in millimeters   
  • Femur Length: Length of the fetal thigh bone, in millimeters   
Back to Calculator		 Illustration of the four measurements on a baby’s body: femur length, abdominal circumference, head circumference, and biparietal diameter.
top of page BACK TO TOP