Third-degree contamination of amniotic fluid may be caused by intrauterine hypoxia and premature defecation due to relaxation of the anal sphincter. Pregnant women with diabetes mellitus, intrahepatic cholestasis, advanced maternal age, and fetal developmental malformations are all prone to intrauterine fetal hypoxia. If the opening of the uterus is large enough for a short delivery and the fetal heart rate is within the normal range, the vaginal delivery can be continued, and if necessary, the delivery can be assisted. If the opening of the uterus is not open or if there is an abnormal fetal heartbeat, it is recommended to deliver the baby by cesarean section immediately. If the newborn’s airway is blocked by contaminated amniotic fluid after delivery, neonatal asphyxia may occur and cardiopulmonary resuscitation should be performed promptly. In addition, newborns with third-degree amniotic fluid contamination are at risk for meconium aspiration syndrome, whether delivered vaginally or by cesarean section, and joint treatment with a neonatologist is recommended.