Enter the depths of the largest vertical pockets of amniotic fluid in each of the four quadrants of the uterus into the calculator to determine the Amniotic Fluid Index.

Amniotic Fluid Index Formula

The following formula is used to calculate the Amniotic Fluid Index (AFI). 

AFI = D1 + D2 + D3 + D4

Variables:

  • AFI is the Amniotic Fluid Index (cm)
  • D1, D2, D3, D4 are the depths of the largest vertical pockets of amniotic fluid in each of the four quadrants of the uterus (cm)

To calculate the Amniotic Fluid Index, add the depths of the largest vertical pockets of amniotic fluid in each of the four quadrants of the uterus.

What is an Amniotic Fluid Index?

The Amniotic Fluid Index (AFI) is a score given to quantify the amount of amniotic fluid seen on an ultrasound of a pregnant woman. It is used to determine if the levels of amniotic fluid are normal, low, or high. This measurement is important because it can help identify potential issues with the pregnancy, such as problems with the baby’s development or the mother’s health. The AFI is calculated by dividing the mother’s abdomen into four sections and measuring the depth of the fluid in each section.

How to Calculate Amniotic Fluid Index?

The following steps outline how to calculate the Amniotic Fluid Index (AFI).

  1. First, measure the depth of the largest vertical pocket of amniotic fluid in the first quadrant of the uterus (D1) in centimeters.
  2. Next, measure the depth of the largest vertical pocket of amniotic fluid in the second quadrant of the uterus (D2) in centimeters.
  3. Next, measure the depth of the largest vertical pocket of amniotic fluid in the third quadrant of the uterus (D3) in centimeters.
  4. Next, measure the depth of the largest vertical pocket of amniotic fluid in the fourth quadrant of the uterus (D4) in centimeters.
  5. Finally, calculate the Amniotic Fluid Index (AFI) using the formula AFI = D1 + D2 + D3 + D4.

Example Problem:

Use the following variables as an example problem to test your knowledge.

Depth of the largest vertical pocket of amniotic fluid in the first quadrant of the uterus (D1) = 5 cm

Depth of the largest vertical pocket of amniotic fluid in the second quadrant of the uterus (D2) = 4 cm

Depth of the largest vertical pocket of amniotic fluid in the third quadrant of the uterus (D3) = 6 cm

Depth of the largest vertical pocket of amniotic fluid in the fourth quadrant of the uterus (D4) = 3 cm