The amount of amniotic fluid in mid to late pregnancy can usually be measured by ultrasound, on the sum of the depths of amniotic fluid in the 4 quadrants, known as the amniotic fluid index, which is normal between 50 and 250 mm. Clinical amniotic fluid index, is to pregnant women’s navel as the midpoint of the cross, imaginary quadrant of the division of the left upper abdomen, left lower abdomen, right upper abdomen, right lower abdomen, ultrasound under the depth of amniotic fluid and sum, > 80mm is normal, if less than 80mm but higher than 50mm, clinically known as the amniotic fluid is less, if the 4 quadrants and less than 50mm, diagnosis of amniotic fluid is too small. Whether the amniotic fluid is low or too low, both are abnormal phenomena, it is recommended that this part of the pregnant women should pay attention to self-counting fetal movement, strict monitoring of the fetal heart, in order to avoid the occurrence of intrauterine fetal hypoxia, or intrauterine fetal death and other extreme events. Therefore, pregnant women with oligohydramnios and oligohydramnios should pay attention to monitoring fetal movement and fetal heartbeat under the guidance of doctors, and if necessary, should be hospitalized to closely monitor fetal movement, fetal heartbeat and amniotic fluid to ensure the safety of the fetus.