What does elevated alpha-fetoprotein mean during pregnancy?

Generally speaking, adults have very little alpha-fetoprotein, and it can only be detected during the fetal period. At 30 weeks of pregnancy, alpha-fetoprotein reaches its peak and then begins to gradually decrease. If the alpha-fetoprotein level is high during the examination during pregnancy, it may not mean anything, because it is probably a normal physiological phenomenon.

Alpha-fetoprotein is a glycoprotein, abbreviated as AFP. Under normal circumstances, this protein mainly comes from the liver cells of the embryo. AFP disappears from the blood about two weeks after the fetus is born. Therefore, the content of AFP in normal human serum is less than 20 micrograms/liter. Alpha-fetoprotein (alpha-fetoprotein, alpha FP or AFP) is mainly synthesized in the fetal liver, with a molecular weight of 69,000. At 13 weeks of fetal development, AFP accounts for 1/3 of the total plasma protein. It reaches its peak at 30 weeks of gestation and then gradually decreases. The plasma concentration at birth is about 1% of the peak, about 40 mg/L, and is close to the adult level (less than 30 mg/L) at one year old.

Fetoprotein can be elevated in the serum of approximately 80% of liver cancer patients, and the AFP positivity rate in germ cell tumors is 50%. Patients with other gastrointestinal tumors such as pancreatic cancer, lung cancer, and liver cirrhosis may also experience varying degrees of increase. It is also one of the main diagnostic steps for diagnosing liver tumors, and of course it must be confirmed with the help of other related examinations.

There are several methods to detect alpha-fetoprotein. If the alpha-fetoprotein measured by radioimmunoassay is greater than 500 micrograms/liter and persists for 4 weeks, or the alpha-fetoprotein is between 200 and 500 micrograms/liter and persists for 8 weeks, after excluding other factors that cause increased alpha-fetoprotein such as acute and chronic hepatitis, post-hepatitis cirrhosis, embryonal tumor, and gastrointestinal cancer, it is necessary to combine positioning examinations such as B-ultrasound, CT, magnetic resonance imaging (MRI) and hepatic angiography to make a diagnosis. However, alpha-fetoprotein may also increase in women with normal pregnancy, in a few cases of hepatitis and cirrhosis, and in malignant gonadal tumors, but the increase is not as high as that in liver cancer.