Abnormalities that are obvious at birth or detectable early in infancy. Also called congenital defects, they encompass both minor abnormalities, such as birthmarks, and serious disorders such as spina bifida.
Causes include chromosomal abnormalities, genetic defects, drugs taken during pregnancy, exposure to radiation, and infections. In some cases, the cause of a defect is unknown. Defects that are due to chromosomal abnormalities include Down’s syndrome. Some defects, such as achondroplasia and albinism, are usually inherited from 1 or both parents (see gene; genetic disorders). Certain drugs and chemicals (called teratogens) can damage the fetus if the mother takes or is exposed to them during early pregnancy. Teratogenic drugs include thalidomide (now rarely prescribed) and isotretinoin, which is used in the treatment of severe acne. Alcohol can affect the development of the brain and face (see fetal alcohol syndrome).
Irradiation of the embryo in early pregnancy can cause abnormalities. Very small doses of radiation increase the child’s risk of developing leukaemia later in life (see radiation hazards).
Certain illnesses, such as rubella (German measles) and toxoplasmosis, can cause birth defects if they are contracted during pregnancy.
Brain and spinal cord abnormalities, such as spina bifida and hydrocephalus, and congenital heart disorders (see heart disease, congenital) result from interference with the development of particular groups of cells. Other common defects include cleft lip and palate.
Ultrasound scanning and blood tests during pregnancy can identify women at high risk of having a baby with a birth defect. Further tests such as chorionic villus sampling, amniocentesis, or fetoscopy may then be carried out.
In 2003, 695,500 live births were registered in the United Kingdom; 38 per cent occurred outside marriage. Overall, total fertility is falling slowly. The number of births per 1,000 women aged over 40 years has been rising, and in 1999 was 8.9 per cent. In Great Britain in 2003, 193,817 legal abortions were performed under the Abortion Act 1967.... birth rate
Birth marks are of various kinds; the most common are port-wine marks (see NAEVUS). Pigment spots are found, very often raised above the skin surface and more or less hairy, being then called moles (see MOLE).... birth marks
Damage sustained during birth. Minor injuries, such as bruising and swelling of the scalp during a vaginal delivery (see cephalhaematoma) are common. More serious injury can occur, particularly if the baby is excessively large and has difficulty in passing through the birth canal. A breech delivery may result in injury to nerves in the shoulder, causing temporary paralysis in the arm. The face may be paralysed temporarily if the facial nerve is traumatized by forceps. Fractured bones are another hazard of difficult deliveries, but the bones usually heal easily. (See also birth defects; brain damage.)... birth injury
(premature birth) birth of a baby before 37 weeks (259 days) of gestation (calculated from the first day of the mother’s last menstrual period); a birth at less than 23 weeks is at present incompatible with life. Such factors as *pre-eclampsia, multiple pregnancies (e.g. twins), maternal infection, and *cervical incompetence may all result in preterm births, but in the majority of cases the cause is unknown. Conditions affecting preterm babies may include *respiratory distress syndrome, feeding difficulties, inability to maintain normal body temperature, *apnoea, infection, *necrotizing enterocolitis, and brain haemorrhages. Supportive treatment is provided in an incubator in a neonatal unit; many infants survive with no residual impairment but the shorter the gestation period, the more serious are the problems to be overcome.... preterm birth
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