Gas phase liquid chromatography (GC) is generally not recommended for pregnant women because the chemical reagents used in GC may affect the fetus. During GC examination, it may be necessary to use some reagents with high volatility, such as acetonitrile, methanol, tetrahydrofuran, etc. It is very likely to inhale toxic gases, which may affect the health of the fetus, and may easily lead to fetal deformities, miscarriages and other undesirable effects, so it is not recommended to perform GC examination during pregnancy. During pregnancy, try to avoid going to the environment that may affect the fetus, keep a good mood, if any physical discomfort occurs during pregnancy, you should go to the hospital for checkups, under the guidance of the doctor for treatment, and do not use drugs indiscriminately.