AFI
Pronunciation: A-F-I
Also written as: AFI — Amniotic Fluid Index
Amniotic Fluid Index, a quantitative ultrasound measurement used to assess amniotic fluid volume during pregnancy.
Full Definition
The Amniotic Fluid Index (AFI) is a standardized ultrasound technique for quantifying amniotic fluid volume by measuring the vertical depth of amniotic fluid pockets in four quadrants of the uterus. The sum of these four measurements provides the AFI value, normally ranging from 5-25 cm. Values below 5 cm indicate oligohydramnios, while values above 25 cm suggest polyhydramnios. The AFI is an important component of antepartum fetal surveillance, as abnormal amniotic fluid volumes can indicate fetal anomalies, placental dysfunction, or maternal conditions. Alternative methods include the single deepest pocket (SDP) technique, which some studies suggest may be more accurate. AFI measurements are routinely performed during third-trimester ultrasounds and as part of biophysical profile assessments.
Usage
Usage note: Always expressed in centimeters; distinguish from SDP (single deepest pocket) measurement.
In Context
- "The AFI measured 3.2 cm, indicating severe oligohydramnios requiring immediate evaluation." — Ultrasound report
- "Serial AFI measurements showed progressive decrease from 12 cm to 4 cm over two weeks." — Surveillance documentation