Before the advent of antisepsis and antibiotics, infection was the commonest cause of death after the first week of life. Now it is much less serious, but still important. Newborn babies often show few if any signs of local infection, but just ‘fail to thrive’ and seem generally unwell.
Respiratory infections, such as pneumonia, may be caused by inhaling blood or liquid during birth, or may be contracted after delivery. Pneumonia is a commoner problem in premature or underweight babies and causes difficulty with breathing. Meningitis is rare but very serious. If a new baby appears unwell for no reason, doctors will probably make sure that meningitis is not responsible, because it often causes no more than a sick, irritable baby. Urinary infections can occur, usually if there is some abnormality of the kidneys or bladder.
Skin infections caused by Staphylococcus bacteria are quite common. Spots, boils and nailbed infections can be treated with antibiotics.
Conjunctivitis is also common, because of a newborn baby’s immature tear ducts.
A widely recognized cause ofin the newborn is haemolytic disease, caused by incompatibility between the baby’s blood group and the mother’s. This is most commonly incompatibility. About 85 per cent of people carry the rhesus factor in their blood cells and are called rhesus positive. (This factor is named after Rhesus monkeys, on which research and tests for it were first performed.) This means that a rhesus-negative woman having a child has an 85 per cent chance of having the child by a rhesus-positive man. If a rhesus-negative woman and a rhesus-positive man have a rhesus-positive baby, problems may occur as follows: if the baby’s and mother’s blood mix – which is not uncommon during birth or abortion, and it can occasionally happen during pregnancy – blood cells from the baby can get into the mother’s circulation. This can trigger the production of antibodies in the mother’s blood which destroy these stray cells. Once they enter the mother’s blood they remain in the mother’s circulation for ever. It is unusual, however, for a first baby of a rhesus-negative woman to be affected. If antibodies are produced in further pregnancies they will cross the placenta and destroy the red blood cells of a rhesus-positive baby. This causes anaemia and , which can either be quite mild, or so severe as to cause stillbirth.
It is now possible to give blood transfusions to affected babies soon after birth, and in modern antenatal centres even while still in the womb if they are badly affected. However haemolytic disease can still be a very severe problem in a new baby. It is important to reduce theif this is serious, because there is a risk of brain damage if a baby’s bile pigment levels are very high.
It is now possible in many cases to prevent rhesus sensitization by giving injections of a serum called Anti-D which destroys any of the baby’s red blood cells in the mother’s circulation before the mother’s body has had time to develop antibodies. These are given to rhesus-negative mothers after childbirth, spontaneous abortion or termination of pregnancy, or as soon as it has been established that the baby’s (or foetus’s) rhesus factor is positive.