P61.1: Polycythaemia neonatorum

Blood is made up of a liquid part and different blood cells, among other things. The blood cells include the red blood cells, the white blood cells and the platelets. The red blood cells carry oxygen from the lungs throughout the body.

There are different reasons why a newborn baby might have too many red blood cells. There may be too many red blood cells if, for example, the child did not have an adequate supply of oxygen in the womb. The body may then produce more red blood cells so that more oxygen can be transported. If the child was in the womb for more than 42 weeks of pregnancy, too, it may have too many red blood cells. A pregnancy usually lasts about 40 weeks. There may also be too many red blood cells if blood was exchanged during pregnancy. Blood may be exchanged between twins, for example. The blood from one twin then flows via the placenta into the other twin's blood circulation system. The placenta forms in the womb during pregnancy.

If the newborn baby has too many red blood cells, the blood thickens and the blood may flow more slowly than usual. There may then be a variety of indications. The newborn baby's breathing may be faster than usual, or it may have breathing problems. The skin may then turn reddish or dark. The baby may then also be lethargic or not drink enough. There may also be no external indications at all, however.