After 34 weeks fetal biparietal diameter 9.4cm to rule out the possibility of fetal hydrocephalus, you can continue obstetric ultrasound to monitor the development. Fetal biparietal diameter is the length of the widest part of the fetal head between the left and right sides, is also the head of the large transverse diameter, is an important indicator to determine whether or not the delivery can be smooth. The normal range of fetal biparietal diameter at 34 weeks of pregnancy is around 8.4cm, and if the fetal biparietal diameter reaches 9.4cm at 34 weeks, it indicates that the biparietal diameter is too large. If the fetal biparietal diameter reaches 9.4cm at 34 weeks of pregnancy, the risk of fetal hydrocephalus should be ruled out by obstetric ultrasound and other examinations. Most of the large biparietal diameter is still physiological, if the pregnant woman’s nutritional supplementation is adequate, there is no need to worry too much, you can continue to monitor the obstetric ultrasound.