<s>[INST] Hi, my wife is expected and after having a ultrasound in the 28th week of pregnancy, there were extrarenal pelvis - right kidney 5.8 and left kidney 4.4. I want to know how safe this after birth and is there any harm of this extrarenal pelvis. Please give me detailed information regarding extrarenal pelvis in kidney of fetus. [/INST] Hello, and I hope I can help you today. An extrarenal pelvis is a variation of the anatomy of the kidneys which is actually found in about 10% of the population. It is absolutely no long-term medical consequences, but it can be confused with other types of urinary obstruction which do not have as good a prognosis therefore it is always important to monitor it if it is seen in a fetus to make sure it is not another more dangerous diagnosis like urinary obstruction. So there are no consequences of the babies health by having an extrarenal pelvis. Many people who have this condition are not diagnosed until they have a test such as an ultrasound of the kidney or CAT scan for another reason and have never had any symptoms over the course of their lifetime. So there's no reason to worry further about the health of your baby because of the extrarenal pelvis. I hope I was able to adequately answer your question today, and that my advice was reassuring. Best wishes to you and your wife for the rest of the pregnancy, </s>