At 38 weeks of pregnancy, the normal value of the amniotic fluid index is between 8 and 18 centimeters, when the amniotic fluid volume is around 1,000 milliliters. If a woman’s amniotic fluid index is less than five centimeters, it is usually called hypoamniotic fluid, which may be due to fetal digestive system abnormalities or urinary system abnormalities, or may be caused by placental hypoplasia, and may also be caused by amniotic membrane lesions, or hypertension during pregnancy, or maternal dehydration and insufficient blood volume. If a woman’s amniotic fluid index exceeds 20 cm, she is said to have excess amniotic fluid, which may be caused by fetal anomalies such as fetal tumors, fetal neuromuscular dysplasia, or fetal spinal bifida, and may be caused by twin or multiple pregnancies, as well as placental cord pathology such as giant placenta, and in cases of combined diabetes during pregnancy. It often leads to hyperosmolar diuresis, which leads to increased leakage of placental membranes, thus causing excess amniotic fluid. Therefore, as long as the amniotic fluid index is normal and the fetal movement is not abnormal at 38 weeks of pregnancy, there is no need for any anxiety or worry, just pay attention to counting the fetal movement.