The reason for seeing red without abdominal pain at 35 weeks of pregnancy may be in the early stages of preterm labor, without obvious uterine contractions, the patient may only have a small amount of redness and abdominal pain only after some time; it may also be related to cervical lesions and placental factors, which should be seen by a doctor in time to avoid delaying the condition.1. Cervical lesions: If a pregnant woman has cervical lesions, she may also have a small amount of redness, but no abdominal pain. It is recommended that pregnant women do an internal examination to look at the surface of the cervix through a speculum to check for abnormal lesions. If some pregnant women have cervical polyps, submucosal fibroids or cervical precancerous lesions, or even cervical cancer, they may have the symptoms of seeing red at 35 weeks of pregnancy without abdominal pain; 2. Placental factors: the most common is placenta praevia, seeing red at 35 weeks of pregnancy without abdominal pain, the distance of the lower edge of the placenta from the inner cervical opening can be determined by ultrasound to diagnose whether it is placenta praevia. In addition, patients with placenta abruptio at 35 weeks of pregnancy may see redness without obvious abdominal pain in the early stage, which often occurs in pregnant women with combined gestational hypertensive disease, although the patient does not have obvious abdominal pain, but may appear abdominal distension, which needs to be combined with the medical history of the pregnant woman and ultrasound examination to confirm the diagnosis. If a pregnant woman has redness at 35 weeks of gestation, but no obvious abdominal pain, it is recommended to go to the hospital in a timely manner, firstly, a 3D ultrasound should be done to observe the development of the fetus and check the condition of the placenta. Secondly, a gynecological examination should be done to check the cervix. If the opening of the cervix is wide, preterm labor may have occurred and hospitalization is recommended for observation and treatment.