Amniotic Fluid Index
Encyclopedia
Amniotic fluid index is a rough estimate of the amount of amniotic fluid
and is an index for the fetal
well-being. It is a part of the biophysical profile
.
AFI is the score (expressed in cm) given to the amount of amniotic fluid seen on pregnant uterus
and calculated by a ultrasonograph (aka ultrasound). To determine the AFI, doctors may use a four-quadrant technique , when the deepest, unobstructed, vertical length of each pocket of fluid is measured in each quadrant and then added up to the others , or the so called "Single Deepest Pocket" technique.
Amniotic fluid
Amniotic fluid or liquor amnii is the nourishing and protecting liquid contained by the amniotic sac of a pregnant woman.- Development of amniotic fluid :...
and is an index for the fetal
Fetus
A fetus is a developing mammal or other viviparous vertebrate after the embryonic stage and before birth.In humans, the fetal stage of prenatal development starts at the beginning of the 11th week in gestational age, which is the 9th week after fertilization.-Etymology and spelling variations:The...
well-being. It is a part of the biophysical profile
Biophysical profile
A biophysical profile is a prenatal ultrasound evaluation of fetal well-being, involving a scoring system. It is often done when a non-stress test is non reactive, or for other obstetrical indications.-The test:...
.
AFI is the score (expressed in cm) given to the amount of amniotic fluid seen on pregnant uterus
Uterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
and calculated by a ultrasonograph (aka ultrasound). To determine the AFI, doctors may use a four-quadrant technique , when the deepest, unobstructed, vertical length of each pocket of fluid is measured in each quadrant and then added up to the others , or the so called "Single Deepest Pocket" technique.
- An AFI between 8-18 is considered normal. Median AFI level is approximately 14 from week 20 to week 35, when the amniotic fluid begins to reduce in preparation for birth.
- An AFI < 5-6 is considered as OligohydramniosOligohydramniosOligohydramnios is a condition in pregnancy characterized by a deficiency of amniotic fluid. It is the opposite of polyhydramnios.-Diagnosis:Diagnosis is made by ultrasound measurement of the amniotic fluid index...
The exact number can vary by gestational age. The fifth percentile for gestational age is sometimes used as a cutoff value.
- An AFI > 20-24 is considered as PolyhydramniosPolyhydramniosPolyhydramnios is a medical condition describing an excess of amniotic fluid in the amniotic sac. It is seen in 0.2 to 1.6% of pregnancies,,...
.