Fetal medullary pool widening is a soft indicator of ultrasound, it is recommended to review the ultrasound regularly when it is under 10mm, and if necessary, perform fetal brain MRI to exclude chromosomal abnormalities. 1. If the width of fetal medulla oblongata is under 10mm, it is recommended to have regular ultrasound examination once every two weeks to dynamically see the change of medulla oblongata widening, and most of them can be absorbed slowly. 2. If the medulla oblongata widening is more than 10mm, there may be hydrocephalus, which will adversely affect the growth and development of the fetus, and in serious cases, it may affect the intelligence of the fetus, so it should be diagnosed and treated in time, and if necessary, it can be examined by MRI of the fetal brain. 3. If the medullary pool is widened, combined with other ultrasound soft index abnormalities, chromosomal abnormalities should be excluded. When the widening of medullary pool is detected, consult the obstetrician in time and individualize the treatment according to the situation.