The presence of cervical mucus with blood in late pregnancy is not necessarily a case of erythema, but may also be an abnormality caused by a woman’s cervical lesions, abnormal placental position, and other conditions. Redness generally refers to the local rupture of small blood vessels in a woman in late pregnancy due to the separation of the fetal membranes from the uterine wall as a result of the descending fetal head pressing on the cervical canal. Within 24-48 hours after the onset of redness, uterine contractions are usually initiated, which is a precursor to the onset of labor. The amount of blood at the time of redness is usually small. If the bleeding increases after cervical mucus with blood, you need to visit the hospital in time to rule out placenta praevia and placenta abruptio. When a woman has cervical mucus with blood, if it does not occur in late pregnancy, it is best to go to the hospital for gynecological examination to see if there is a cervical lesion, or the occurrence of pre-eclampsia or preterm labor, so as not to delay the diagnosis and treatment, and affect the health of the fetus and the pregnant woman.