NT thickening is not related to folic acid, which is taken orally during the first 3 months of pregnancy and the second 3 months of pregnancy to prevent neural tube abnormalities in the fetus. Fetal neural tube abnormalities are mainly manifested as anencephaly, cerebral bulge, cerebrospinal bulge, spina bifida, cleft lip, cleft palate, etc. Folic acid deficiency can affect the closure of fetal neural tube, so oral folic acid can prevent fetal neural tube abnormality during pregnancy, NT refers to the thickness of the nuchal translucency layer during 11-13 weeks plus 6 days of pregnancy, if the NT is greater than 3mm, the fetus will have a high risk of Down syndrome, and further Down screening or amniocentesis is needed to confirm the diagnosis. Fetal neural tube abnormality and Down’s syndrome are not the same type of disease, so NT thickening is not related to whether or not to take oral folic acid.