family risk of inherited disease, and carrier screening with genetic counselling, enable couples to limit family size where there is a known risk. 10. Prevention during pregnancy requires risk identification and management. Some of the interventions and services related to this can raise ethical, legal and social issues and may have cost implications. Such services include prenatal screening and diagnosis for birth defects, selective termination of pregnancy, and the availability of counselling services. Minimally invasive screening methods are currently available, such as taking maternal blood for the measurement of several metabolites in the maternal serum. Abnormal levels of biochemical markers are also associated with fetal structural defects such as Down syndrome, neural tube defects and open ventral wall defects. The A63/10 3 detection rate of congenital disorders in the first trimester through biochemical screening is improved when it is undertaken in tandem with ultrasound screening involving nuchal translucency and other ultrasonographical assessments. Ultrasonography in the second trimester is useful to detect major structural defects. DETECTION, TREATMENT AND CARE 11. Screening of newborn infants for congenital disorders facilitates early detection, treatment and care. Neonatal screening programmes (physical examination of all neonates and screening for congenital hypothyroidism, phenylketonuria, sickle-cell disease and glucose-6-phosphate dehydrogenase deficiency) and training of primary health-care providers support the diagnosis and appropriate referral for treatment of infants with congenital disorders. Physical examination of all newborn infants by trained primary health-care practitioners is feasible in most health systems and allows the identification of many birth defects, including cardiovascular defects that are associated with a high risk of early mortality and referral. 12. Treatment of birth defects depends on the level of health care available. It comprises medical therapy, surgery, rehabilitation and palliative care when appropriate. 13. Effective life-saving medical treatment is available for several birth defects, including some common functional single-gene defects. Examples include treatment of neonatal jaundice in glucose6-phosphate dehydrogenase deficiency and in Rhesus incompatibility, and therapy for congenital hypothyroidism, sickle-cell disorders, thalassaemia, haemophilia, cystic fibrosis, and other inborn errors of metabolism. Other treatment options include in utero therapy and postnatal surgical corrections; these are now under research and evaluation in a few selected centres for a number of conditions (e.g. congenital diaphragmatic hernia, congenital heart lesions, myelomeningocele, twin-totwin transfusion syndrome). 14. Surgery is an important but largely unheralded component of the services required to treat children with birth defects. More than 60% of children with a birth defect have a congenital malformation of a single organ, system or limb. Many birth defects are amenable to cost-effective surgery that can be life-saving and improve long-term prognosis. Examples are surgery for simple congenital heart defects, cleft lip and palate, club foot, congenital cataracts, and gastrointestinal and urogenital abnormalities. 15. Appropriate treatment is also needed for impairments manifesting themselves after the neonatal period. This includes the early detection and treatment of physical, mental, intellectual or sensory impairments. Access to health and rehabilitation services is important to support the participation and inclusion of affected children. 16. With appropriate training, primary health-care practitioners can offer basic care for children with birth defects. They are able to recognize birth defects, diagnose common problems and identify associated disabilities, which in turn enables them to offer basic treatment and counselling, taking into account family and community circumstances and available medical services. Referral to specialist advice is considered when diagnosis is not possible at the primary health-care level. A63/10 4 IMPLICATIONS FOR SERVICES 17. Services and interventions for the prevention and care of birth defects should be part of existing health-care services, in particular those concerned with maternal and child health. They should combine the best possible patient care with a preventive strategy encompassing education, pre-conception care, population screening, genetic counselling, and the availability of diagnostic services. That strategy must deliver services for the prevention and care of birth defects as part of a continuum of interventions for maternal and child health. Depending on countries’ health-care capacities, these services should go beyond primary health care to include obstetric, paediatric, surgical, laboratory, radiological and, if available, clinical genetic services in secondary and tertiary health care. 18. Effective delivery of services for the prevention and care of birth defects depends on the availability of a range of specialist clinical and diagnostic services, and a primary health-care system that is able to use them. A nucleus of expertise in medical genetics, paediatric surgery, imaging, and fetal medicine is required, with the potential to expand to meet needs. Conventional laboratory services (haematological, microbiological, and biochemical)