4 months postpartum holding urine for too long will have blood, if occasionally a very small amount of short-term bleeding is relatively normal, if the bleeding time is too long or other discomfort, but also to rule out the presence of urinary tract inflammation, tumors, and reproductive organs, inflammation and tumors. Generally speaking, the genitourinary organs will return to normal in about 2-8 weeks after delivery, and the function of the genitourinary system should return to normal in 4 months after delivery. The bladder mucosa is in a diastolic state due to the increased pressure in the bladder after holding back the urine, rapid urination, the pressure in the bladder will drop abruptly, which will easily cause small blood vessels to dilate dramatically, resulting in rupture and bleeding, this situation is generally considered normal if only a short period of time and occasional bleeding, the amount of bleeding is very small, and there is no other obvious discomfort. If the frequent occurrence of too much bleeding after holding urine for too long, bleeding time is too long, accompanied by abdominal pain, nausea, vomiting, sweating and other abnormalities must go to the hospital in time to rule out whether there is urinary tract inflammation, tumors, and inflammation of the reproductive organs and tumors. It is recommended to go to the hospital to do a urogenital tract ultrasound examination, routine urinalysis, vaginal secretion examination, gynecological examination, etc., according to the specific examination of the situation of the doctor’s orders for timely and symptomatic treatment.