During pregnancy there has been occult blood +3 red blood cells 3-5 generally refers to the results of routine urinalysis, considering urinary tract infection, kidney stones, glomerulonephritis and so on. 1. urinary tract infection: urinary tract infection is caused by pathogenic microorganisms, which can lead to mucosal congestion and edema of the urinary tract, and may even have ulcers, so there will be a small amount of bleeding, urine examination will appear occult blood +3 red blood cells 3-5, usually accompanied by urinary symptoms such as frequent urination, urinary urgency. 2. Kidney stones: Kidney stones are formed in the kidney by some components in the urine, and the movement of kidney stones in the kidney will stimulate the mucous membrane of the renal calyx, and a small amount of bleeding, some patients may be accompanied by symptoms of back pain, and if the stones are relatively small, there may not be too obvious clinical symptoms. 3. Glomerulonephritis: Glomerulonephritis is caused by a variety of reasons, glomerular injury with inflammation, glomerulonephritis will lead to the destruction of the filtration barrier of the kidneys, and the red blood cells will be discharged from the kidneys, so there is occult blood plus 3 and red blood cells 3-5. During pregnancy there has been occult blood +3 red blood cells 3-5, there may also be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.