What is the normal range of amniotic fluid index?

Too much or too little amniotic fluid is not good for the health of the fetus, so we need to pay attention to the normal index of amniotic fluid. Under normal circumstances, if AFI ≥ 25cm, it means too much amniotic fluid, and if AFI ≤ 5cm, it means too little amniotic fluid.

1. Amniotic fluid index:

The uterus is divided into four quadrants: upper left, upper right, lower left and lower right. The sum of the maximum vertical depths of the dark areas of amniotic fluid in the four quadrants is the amniotic fluid index (AFI). AFI ≥ 25cm is diagnosed as polyhydramnios, among which AFI 25-35cm is mild polyhydramnios, 36-45cm is moderate polyhydramnios, and >45cm is severe polyhydramnios; AFI ≤ 5cm is diagnosed as oligohydramnios, and ≤ 8cm is oligohydramnios.

2. Depth of amniotic fluid:

Ultrasound examination indicates the vertical depth of the largest amniotic fluid pool. ≤2cm indicates oligohydramnios, and ≥8cm indicates polyhydramnios. It is a medical term and an important indicator for determining the amount of amniotic fluid. When there is too much amniotic fluid, pregnant women are prone to complications of gestational hypertension, premature rupture of membranes, abnormal fetal position, and premature birth. When there is too little amniotic fluid, the perinatal mortality rate increases significantly. Ultrasound examination shows the vertical depth of the largest amniotic fluid pool. A depth of 3-7cm is considered normal.

3. Amniotic fluid measurement:

The measurement of amniotic fluid volume is an important indicator to assess whether the pregnancy is normal. Currently, most hospitals use ultrasound to understand the amount of amniotic fluid and adopt the "amniotic fluid index method" to determine whether the amount of amniotic fluid is normal. The method is: divide the uterus into four quadrants, measure the maximum depth of the amniotic fluid in each quadrant, and then add up the total. A total value between 9 and 24 cm is considered normal, ≤8 indicates oligohydramnios, ≤5 indicates oligohydramnios, and ≥25 cm indicates polyhydramnios.