The amniotic fluid index is less than 8cm and the maximum depth of individual amniotic pool is less than 3cm, which is too little amniotic fluid. If the amniotic fluid is too small and the contractions are used to induce labor, the umbilical cord cannot be protected by amniotic fluid and the uterine wall can directly compress the umbilical cord during contractions, resulting in impaired blood circulation. If the fetal ischemia and hypoxia is serious, it may cause intrauterine distress or asphyxia, so if the amniotic fluid is too small, the risk to the fetus is greater if the delivery is carried out with amniotic fluid. However, if the amniotic fluid is between 8-5cm, the fetus is not very big, and the pelvis and cervical maturity of the pregnant woman are very good, the delivery can be finished in a short time, and the delivery can be done under close fetal heart monitoring.