If the ventricles of the brain are not widened at the time of ultrasound, but are widened at the time of systematic screening after 15 days, it may be due to measurement errors, fetal hydrocephalus, or intracranial occupying lesions.
1. Measurement error: There is some error in measuring the relevant data during the ultrasound examination.
2. Fetal hydrocephalus: there are certain changes in the fetus in the uterus of the pregnant woman. During the 4D ultrasound examination, the fetus is normal and does not show any abnormality, but hydrocephalus may appear when the systematic screening is conducted after 15 days, causing widening of the lateral ventricles.
3. Fetal intracranial space-occupying lesions: some cranial and cerebral space-occupying lesions, which may be small and undetected during 4D ultrasound, may show widening of the ventricles when systematic screening is performed after 15 days.
If the ventricles are not widened during the 4D ultrasound but are widened after 15 days of systematic screening, it is recommended to conduct a comprehensive examination to identify the specific cause of the disease and then target treatment.