Amniotic fluid index | |
---|---|
Purpose | estimate of amniotic fluid and an indicator of fetal well-being |
Amniotic fluid index (AFI) is a quantitative estimate of amniotic fluid [1] and an indicator of fetal well-being. It is a separate measurement from the biophysical profile. [1]
AFI is the score (expressed in centimetres) given to the amount of amniotic fluid seen on ultrasonography of a pregnant uterus. To determine the AFI, doctors may use a four-quadrant technique, [2] when the deepest, unobstructed, vertical length of each pocket of fluid is measured in each quadrant and then added up to the others, [3] or the so-called "single deepest pocket" technique. [4]
An AFI between 8 and 18 cm is considered normal. [5] Median AFI level is approximately 14 cm from week 20 to week 35, [6] when the amniotic fluid begins to reduce in preparation for birth. An AFI smaller than 5–6 cm is considered as oligohydramnios. [3] The exact number can vary by gestational age. The fifth percentile for gestational age is sometimes used as a cutoff value. [7] An AFI larger than 24–25 cm is considered as polyhydramnios. [3] [8]
There are many things that can cause low AFI, these include:
Amniotic fluid index | |
---|---|
Purpose | estimate of amniotic fluid and an indicator of fetal well-being |
Amniotic fluid index (AFI) is a quantitative estimate of amniotic fluid [1] and an indicator of fetal well-being. It is a separate measurement from the biophysical profile. [1]
AFI is the score (expressed in centimetres) given to the amount of amniotic fluid seen on ultrasonography of a pregnant uterus. To determine the AFI, doctors may use a four-quadrant technique, [2] when the deepest, unobstructed, vertical length of each pocket of fluid is measured in each quadrant and then added up to the others, [3] or the so-called "single deepest pocket" technique. [4]
An AFI between 8 and 18 cm is considered normal. [5] Median AFI level is approximately 14 cm from week 20 to week 35, [6] when the amniotic fluid begins to reduce in preparation for birth. An AFI smaller than 5–6 cm is considered as oligohydramnios. [3] The exact number can vary by gestational age. The fifth percentile for gestational age is sometimes used as a cutoff value. [7] An AFI larger than 24–25 cm is considered as polyhydramnios. [3] [8]
There are many things that can cause low AFI, these include: