The symptoms of redness when women hold urine during pregnancy may be caused by the following factors: 1, it may be caused by infection in the urinary system, if cystitis or urethritis occurs during pregnancy, the symptoms of redness after holding urine will occur, accompanied by frequent urination, urinary urgency and other symptoms, you need to take antibiotics for treatment under the guidance of a doctor, such as amoxicillin 2, may also be due to pre-eclampsia or preterm labor and other factors, need to go to the hospital for ultrasound and other related examinations, and then under the guidance of the doctor, take fetal preservation drugs for treatment, such as fetal pills, but also under the guidance of the doctor, intravenous drip magnesium sulfate and other drugs for treatment, while the patient should also pay attention to bed rest and supplemental nutrition.