The causes of high alanine aminotransferase in pregnant women may be related to medications and diseases, such as viral hepatitis, cholestasis, preeclampsia and so on. 1. Drugs: In early pregnancy, many pregnant women will take folic acid or DHA supplements, etc. The above drugs may lead to the elevation of this enzyme in some pregnant women, but this cause will not cause any discomfort to the pregnant women. 2. Disease factors (1) Viral hepatitis: If pregnant women have viral hepatitis, it may lead to the destruction of liver cells, and this enzyme is easy to be elevated at this time, and the increase of this cause is generally larger, and pregnant women may be accompanied by nausea, fatigue and other symptoms. (2) Cholestasis: If cholestasis occurs during pregnancy, the main cause is the elevation of bile acids, but some pregnant women may show high levels of this enzyme. (3) Pre-eclampsia: If a pregnant woman develops pre-eclampsia, it may appear as HELLP syndrome. The main manifestation of HELLP syndrome is the elevation of alanine aminotransferase, and there is also a decrease in platelets. Therefore, pregnant women with high alanine aminotransferase need to consult a doctor in time to identify the cause of the disease before treatment, so as to avoid adverse effects on the pregnant woman and the fetus.