I'm 27 weeks pregnant. My OB just told me that I have had traces of blood in my urine in all my urine tests since pregnancy. He said that it was probably due to kidney or bladder problems, and that he could do nothing about it during my pregnancy. He suggested I have a thorough test three months after delivery and said not to worry for the time being. I have no history of kidney or bladder problems, and I'm concerned about what this might mean. Can you shed some light on this?

--Ada

I must respectfully disagree with your doctor about not being able to do anything about blood in the urine during pregnancy. Blood in the urine may be due to a bladder or kidney infection; this may be assessed by doing a simple urine culture and, if infection is confirmed, treated with antibiotics that are safe to use during pregnancy. Untreated urinary tract infections in pregnancy increase the risk of preterm labor and delivery.

Blood in the urine may also be due to a kidney stone. Ultrasound or a single shot IVP (an X-ray test) may be done to diagnose this condition. Kidney stones may be difficult to remove during pregnancy, as lithotripsy -- smashing the stones with sound waves -- cannot be done, but secondary infections can be treated, and pain relief can be provided.

Blood in the urine may also be a sign of bladder cancer. Although bladder cancer is rare in the age group in which women generally become pregnant, I will never forget a case we diagnosed while I was a resident -- a 32-year-old pregnant with her fourth child. By treating this cancer aggressively as soon as it was found, we were able to give this women a good chance of seeing her kids graduate from high school. Cancer can be diagnosed during pregnancy by performing cytology on a urine sample or by a procedure called cystoscopy to look into the bladder.

Medical conditions such as lupus, sickle cell anemia or diabetes may also affect the kidneys and cause blood in the urine. In many of these medical conditions, elevated amounts of protein will be present as well. A thorough history and physical exam, along with carefully selected laboratory testing, will lead to the proper diagnosis in most cases.

Persistent blood in the urine must be investigated, whether or not you are pregnant. If a urinary tract infection is ruled out on the basis of a negative culture result, and if there are no obvious medical conditions present that could account for the blood, a consultation with a urologist is the next step. If blood has been present on every urine test for the last 27 weeks (probably encompassing about five to seven office visits), it must not be ignored. Insist upon a Make sure to mention these concerns with your doctor. If he is unwilling to do a further work-up, I would go for a second opinion.