Question
What’s wrong if a newborn’s urine contains blood?
Answer
This is a physiological phenomenon in newborns, referred to as “false menstruation.” The reason for this phenomenon is that during the late stages of pregnancy, the mother transfers estrogen to the fetus, which stimulates the proliferation and congestion of the female infant’s reproductive tract mucosa. After birth, with the source of estrogen from the mother interrupted, the estrogen levels in the female infant’s body also drop sharply, reaching a very low level within 3-5 days. The supportive effect of estrogen on the proliferation and congestion of the reproductive mucosa is also interrupted, causing the previously proliferated and congested endometrium to shed, resulting in a small amount of blood and some purulent discharge being excreted from the vagina. This presents similarly to menstruation, hence the term “false menstruation.”