The uterus is divided into four quadrants. Lines of demarcation: longitudinal: linea nigra; transverse: umbilicus.

The deepest vertical pocket of AF is measured in the four quadrants.

The sum of the depths of AF in the four quadrants = AFTI.

Normograms are available.

Qualitative measurement — mild, moderate or severe.

Quantitative measurement — single vertical pocket :

AF>8cm.

AFT 24 cm = clinically significant PH.

Qualitative measurement — visual lack of AF, poor fluid/fetal interface and crowding of fetal parts.

Quantitative measurement — largest pocket of AF <2cm

AF volume <300 ml at term

<3rd centile for gestation.