In the middle of pregnancy, a woman’s blood is drawn to check her body’s alpha fetoprotein, which is used to determine the health of the fetus. Most of the tests are performed between 16 and 20 weeks of pregnancy and the normal value is not more than 40 mg/L. If a mother’s AFP is too high, she usually has anencephaly or spina bifida, the normal value of AFP is around 50 mg/L at 15 weeks of pregnancy and 70 mg/L at 18 weeks of pregnancy. 93mg/L is normal, and above 20mg/L there will be no problems.