Occasional leakage of urine in the third trimester of pregnancy may be normal and related to an enlarged uterus pressing on the bladder. It may also be abnormal and related to urinary tract infection. When the fetus develops gradually in the uterus in the third month of pregnancy, the uterus will gradually increase in size, and the uterus compresses the nearby organs, such as the bladder and ureter, and then urine leakage occurs, which is a normal phenomenon, and occasional leakage does not require special treatment. Occasional leakage of urine during 3 months of pregnancy may also be caused by urinary tract infections, such as urethritis, cystitis, stimulated by inflammation may have occasional leakage of urine, some women will be accompanied by urinary pain, frequent urination, urinary urgency, hematuria and other symptoms, this situation is abnormal, should be promptly consulted and treated. Leakage of urine during pregnancy should pay attention to the perineum cleanliness and hygiene, underwear should be replaced in a timely manner clean, patients with urinary tract infections can take medication under the guidance of a doctor, such as cephalosporin antibiotics, every day should also be appropriate to drink more water and urinate more. The third month of pregnancy should pay attention to more observation of the body changes, there are abnormalities in a timely manner to seek medical attention.