What can cause blood in urine during pregnancy?

"There are multiple reason for blood in the urine during pregnancy but the commonest among them and which are usually found are either urinary tract infection or stone or the calculus in urinary tract. Urinary tract infection can affect pregnancy because if it is very severe, it can give rise to premature delivery. So usually when we do the urine testing during pregnancy, if there are bacteria or pus cells found, we do the culture tests and treat it before the patient is symptomatic. Stones during pregnancy, if it is not symptomatic, need not be treated. But if they are there patient can get severe pain in abdomen, and they are difficult to diagnose in advanced pregnancy because they are not usually seen in ultrasound. So if the symptoms or the blood in the urine say that there is stone, the treatment usually is conservative. They do not affect the pregnancy directly. Because the patient is having severe pain, we need to treat them"