There is no relationship between umbilical cord knot and mental retardation, and not all babies with umbilical cord knots are mentally retarded.
If the knot is not tightened, it may be a false knot in the umbilical cord, which does not have much effect on the fetus and does not affect the blood circulation of the fetus, and the tightness of the knot can be observed by means of ultrasonography and fetal heart rate monitoring in the normal course of events.
If the umbilical cord is too long, it is necessary to pay attention to the presence or absence of the cervical cord, and when the fetus is full term, it can be delivered by cesarean section as soon as possible, and usually it will not affect mental retardation.
If the knot is tightened and the umbilical cord becomes a true knot, it will affect the circulation of the fetal blood. If the fetal blood circulation is obstructed and the baby suffers from hypoxia at the critical time of brain and nerve development, the baby may suffer from mental retardation, which may also lead to abnormal development of the fetal heartbeat and fetal movement, so it is necessary to monitor the physiological indicators of the fetus, such as the heart rate and the development of the fetus more closely.
In conclusion, the degree of impact of umbilical cord knotting on the intelligence of the baby needs to be determined by a specialist based on the monitoring indicators.