Whether yellowing of the leukorrhea during pregnancy will affect the fetus depends largely on the severity of the condition. Yellowish leucorrhea during pregnancy only may be caused by vaginal inflammation and a routine leucorrhea test is recommended to check the leucorrhea condition. Since the fetus is inside the amniotic cavity, which is a complete closed intrauterine environment, it is difficult for bacteria to enter the uterine cavity through the amniotic sac to cause infection in milder inflammation. In this case, the symptoms can be improved by washing the pubic area with warm water, which usually does not affect the fetus. If the inflammation is severe, combined with itching, odor and other symptoms, you should promptly consult a gynecologist to avoid retrograde infection, so that bacteria can enter the uterine cavity and cause intrauterine infection, which will affect the fetus. Usually women are in a state of low immunity during pregnancy, it is recommended that pregnant women wash their vulva with light salt water, change their underwear regularly, wear loose and breathable cotton underwear, and keep their vulva clean and dry to avoid vulvar inflammation.