The normal range of amniotic fluid index at 30 weeks of pregnancy is usually around 80-180mm. The amount of amniotic fluid during pregnancy usually needs to be judged according to the index of amniotic fluid under ultrasound, with the umbilical level and abdominal white line as the mark to divide the uterus into four quadrants at right angles, ultrasound measurement of the maximum amniotic pool of the vertical radius of each quadrant, the sum of the four is the index of amniotic fluid, the index of the normal range of the index is generally in the range of about 80-180mm in 30 weeks of pregnancy. If the index of amniotic fluid is <50mm, the amount of amniotic fluid is too low, which may be related to fetal urinary tract anomalies, placental malfunction, maternal dehydration, etc. Low amniotic fluid during pregnancy will also increase the risk of fetal anomalies. If the index of amniotic fluid is >250mm, it belongs to excessive amniotic fluid, which may be related to fetal anomalies, gestational diabetes, etc. It will lead to weak contractions, prolonged labor, and preterm labor. Mothers are advised to go to the hospital for regular checkups, and if there is any discomfort, timely treatment is needed to avoid delaying the condition and causing adverse consequences.