16 weeks pregnant urine test leukocytes 3 + may be urethritis, pyelonephritis, etc., if the symptoms are light, generally not serious timely treatment can be, if the symptoms are heavy, may cause complications, is more serious. 1. Urethritis: pathogenic bacteria infection to the urethra will cause acute and chronic inflammation of the urethra, for non-gonococcal urethritis, usually no obvious symptoms, if it is gonococcal urethritis, this situation is more serious, and even combined with the infection of the reproductive organs, threatening the health of pregnant women and the fetus, it is more serious. 2. Pyelonephritis: pregnant women during pregnancy uterine enlargement, ureteral contraction function is weakened, easy to discharge restrictions, pathogenic bacteria infected to the renal pelvis and renal parenchyma, resulting in acute and chronic inflammation, if the condition is not controlled in time will lead to complications, preterm labor, low fetal weight, and even lead to fetal malformation, abortion, etc., this is a more serious situation. Urine test at 16 weeks of pregnancy leukocytes 3 + should be timely communication with the doctor, combined with clinical symptoms and other tests comprehensive diagnosis and active treatment, do not delay the condition.