Although the majority of newborn babies are quite normal andy, there are a number of illnesses that can affect them. Some start in the womb, others develop after birth. Infections constitute the largest group of newborn-related .
The placenta is generally quite an effective barrier against, although there are a few organisms which can cross it and cause infections in the foetus, the effects of which are often still apparent at birth. Common infections such as measles or chickenpox caught in late pregnancy can cause a baby to be born with the illness, although it will not be severe. The most serious and worrying infection during pregnancy is rubella, or German measles. If a mother catches this during the first three to four months of pregnancy it can cause serious abnormalities in the foetus, and even intrauterine death. The common effects are cardiac abnormalities such as holes in the heart and failure of the ductus arteriosus to close, or ear and eye malformations. When a mother has the illness during the first 12 weeks of pregnancy, there is a risk that a baby will have a number of these problems, and this is called congenital rubella syndrome. If caught later in pregnancy, the risks are much smaller, but in all cases the baby remains infectious for some time after birth. Expectant mothers can be screened for immunity to rubella at the first antenatal clinic appointment, and it is hoped that the incidence of this severe congenital infection will decrease with the offer of anti-rubella vaccination to school-age girls.
There is another virus disease which is much less common, but which can also result in congenital abnormalities if the mother is infected in early pregnancy. This is caused by cytomegalovirus. It producesand anaemia in the , and can also cause microcephaly or hydrocephalus (abnormally large amounts of fluid in the brain) and eye abnormalities.
Congenital syphilis is now a rarity in developed countries, but a routine test for syphilis is normally carried out at the first antenatal appointment all the same. If the test turns out to be positive the woman can be treated with penicillin. Syphilis usually affects the foetus after the first three or four months, so has different effects from rubella. At its worst it can cause stillbirth.
Less severe syphilitic infections cause theto show signs of anaemia, poor growth and skin . These effects do not become obvious for a few weeks after birth. Another venereal disease, gonorrhoea, can cause serious eye infections in the new baby, but these can be treated easily using eye-drops or sterile water.
More than 50 per cent of newborn babies have ‘physiological’ jaundice. It is caused by a build up of bilinibin*, the yellow bile pigment which the baby’s immature liver cannot excrete efficiently.
More severe jaundice can be a sign of infection of some kind, and very rarely results from genital blockage of the bile ducts or enzyme deficiencies.
Infections during birth
Thrush is a common vaginal infection which can be passed on to a new baby during his or her passage through the birth canal. It usually causes only mouth infection, which may give difficulty with feeding, but can easily be treated with medication.
A more serious infection which can be present is genital herpes. This sexually transmitted disease is characterized by a crop of small blisters which can burst to leave painful ulcers. If the virus is active during birth, giving rise to severe infection, causing fits and severe mental retardation. If a mother is found to have active genital herpes at the time of birth she will be advised to have a Caesarian section to deliver her baby.