Whether the head size of the fetus is normal or not needs to refer to the patient’s condition, some fetuses are normal manifestations and some are abnormal manifestations. Fetal head size will continue to grow with the growth and development of the fetus, due to individual differences in fetal development, some of the fetus’s head size will be higher than the average level of the fetus in the same gestation period, but not more than two standard deviations from the average, which is a normal development of the fetus. If the head size of the fetus is abnormally large, obviously higher than the average level of the same pregnancy, and higher than two standard deviations, you should check the gestational week again, to make sure whether there is an error in the calculation of the expected date of delivery, and if necessary, you need to carry out further examination to rule out the presence of hydrocephalus and other malformations in the fetus. If the fetus is abnormal, it should be treated as early as possible under the guidance of specialized physicians to avoid adverse pregnancy outcomes.