The normal value of the amniotic fluid index at 28 weeks of gestation is 8-25 cm. The amniotic fluid index is obtained by dividing the amniotic cavity into four quadrants from the navel and measuring the maximum amniotic fluid depth in each quadrant and adding them together. The maximum amniotic fluid depth is the maximum measurement of the depth of amniotic fluid in the amniotic cavity and should be within the normal range of 3-8 cm. The amniotic fluid index changes significantly in different weeks of gestation, with the amount of amniotic fluid gradually increasing after the middle of pregnancy as the gestational weeks increase, reaching a peak at 32 weeks and gradually decreasing in the last 2-4 weeks. If there is too much amniotic fluid or too little amniotic fluid, you must consult a doctor in time. Amniotic fluid abnormalities are usually divided into the following two types: 1. too much amniotic fluid: amniotic fluid index > 25 cm, suspected fetal abnormalities, chromosomal abnormalities or twin pregnancies, diabetes, pregnancy combined with maternal and child blood type disorders, etc. Therefore, we should investigate each case, regular ultrasound examination to understand the size of the fetus and the amount of amniotic fluid, testing blood sugar, urinary routine, etc., to prevent infection; 2. amniotic fluid Too little amniotic fluid: amniotic fluid index <8cm, suspected of insufficient water intake, gestational hypertension, abnormal placental function, fetal congenital urethral agenesis, etc. If caused by insufficient water intake, the amount of amniotic fluid can be increased by infusion. Pregnant women should also pay attention to large amounts of water and drink more soy milk or other nutritious soups on a daily basis.