If the fetus has cystic mass in the sacrococcygeal region, it is considered that it may have caudal cyst or spinal bulge, and it needs to be screened for fetal malformation in 4D. If it is a simple sacrococcygeal cyst, it can be treated surgically after birth and usually recovers quickly after surgery. If it is a fetal spinal bulge, which is a neurovascular malformation, it is recommended to take folic acid before the next pregnancy, stay away from radiation and dangers, and do not take any medication that has an effect on the fetus. Folic acid supplementation can effectively prevent fetal neural tube abnormalities. Take 0.4mg of folic acid from the first trimester of pregnancy, at least until the second trimester, preferably throughout the pregnancy. If you have had a child with neural tube abnormality, you should take 4mg of folic acid daily and also consume more folic acid-rich foods such as animal liver, kidney, eggs, beans, green leafy vegetables, fruits and nuts, etc.