The technology has been available to detect carriers of haemoglobin di
sorders since the late 1960s. Prenatal diagnosis has been available si
nce 1978. First trimester diagnosis by chorionic villus sampling and D
NA analysis was introduced in 1982, and subsequent simplifications in
DNA technology have made screening, counselling and prenatal diagnosis
cost-effective at the community level, in countries at all levels of
development. Audit of prenatal diagnosis for haemoglobin disorders in
countries which have the resources and infrastructure necessary for ge
netic population screening (such as the UK and other European countrie
s), has shown that the number of prenatal diagnoses actually performed
fall far shea of expectation. The demonstration that this reflects fa
ilures in delivering information, screening and counselling to the pop
ulations at risk, rather than rejection of prenatal diagnosis, shows t
he importance of placing more emphasis on the organisational and socia
l requirements for genetic population screening. In some countries cur
rent attitudes towards abortion exclude provision of prenatal diagnosi
s within the health service, but in many such cases it has been set up
in the private sector. It is also being introduced through combined p
rivate and charitable efforts in an increasing number of developing co
untries, including some with extremely limited health resources: such
centres are likely to act as nuclei for emergence of genetics services
in these communities. A particularly notable recent achievement is th
e introduction of prenatal diagnosis in Nigeria, where 1-2% of all chi
ldren born suffer from sickling disorders.