At 34 weeks pregnant, the biparietal diameter is 91MM, the head-to-tail length is 328MM, the abdominal circumference is 329MM, and the femur length is 65MM, the humerus length is 59MM. The doctor suggests visiting a higher-level hospital for a follow-up examination! Is a larger-than-normal fetal head size a sign of hydrocephalus? Why can’t the ultrasound detect hydrocephalus?