Tag: Polyhydramnios

Amniotic fluid index

Amniotic fluid index

• Imagine the uterus in 4 parts and in these 4 parts measure the single largest vertical pocket.

• Here in this image the uterus is divided into 4 quadrants and the single largest vertical pocket namely A, B, C & D are measured.

• AFI= A+B+C+D= 5-24 (NORMAL)

• >25 cm is polyhydramnios & <5 cm oligohydramnios.

• AFI is not appropriate to use in twin pregnancy. Therefore, the best sensitive method is to measure single Deepest vertical pocket (SDP).

Amniotic fluid index explained with images



  1. Mild- pockets measuring 8-11 cm in the vertical dimension (seen in 80% cases).

  2. Moderate- as pocket measuring 12-15 cm in the vertical dimension (seen in 15% cases).

  3. Severe- free-floating fetus found in pockets of fluid of 16 cm or more (seen in 5% cases).




→ It is a condition where liquor amnii is in excessive amount i.e. > 2 liters/ 2000ml.

→ M/C used definition is by ultrasound assessment, i.e.

  1. When the amniotic fluid index (AFI) is > 25 cms.

  2. Or finding a pocket of fluid measuring 8 cm or more in vertical diameter.

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