Checking for Down's syndrome
By Niall Hunter-Editor
The prospect of having
a baby with Down syndrome cause considerable anxiety among women, particularly
those over the age of 35.
There are tests available
to check for this type of fetal abnormality, but they are carried out late
in the pregnancy and also carry with them the risk of a possible miscarriage.
in ultrasound and blood tests now mean that women can have effective for
Down syndrome carried out earlier in the pregnancy and without any possible
risks of miscarriage being induced by the test.
A major new study headed
by an Irish consultant has shown that over 95% of Down syndrome cases can
now be detected in early pregnancy.
Results of the study published
in the New England Journal of Medicine demonstrate that new ultrasound
and blood tests are now widely available that can detect over 95% of cases
of Down syndrome as early as 10 to 12 weeks into a pregnancy.
Over 38,000 pregnant women
were provided with a range of ultrasound and blood screening tests at 10
to 13 weeks and then at 15 to 18 weeks gestation.
The study found that screening
in the first three months of a pregnancy provided a detection rate of Down
syndrome of up to 87%, and that other combinations of screening produced
a detection rate of 96%.
The leader of the study,
which involved the coordination and analysis of results from 15 US centres,
was Prof Fergal Malone, Chairman of the Department of Obstetrics and Gynaecology
at the Royal College of Surgeons in Ireland and the Rotunda Hospital.
Prof Malone said concern
regarding Down syndrome causes considerable anxiety for pregnant women,
especially those aged over 35.
He said the testing approach
adopted in the study picks up over 95% of cases of the condition, which
is a huge step forward and provides reassurance to the vast majority of
women in the very early stages of pregnancy.
Traditional tests for
Down syndrome, chorionic villus sampling or amniocentesis, both carry a
small risk of miscarriage.
Prof Malone says the new
research shows that the vast majority of women can avoid these tests by
using ultrasound and blood tests instead.
These pose no risk to
pregnancy and give reassurance to the patient early on.
He added that women who
are interested in the reassurance that these tests provide should be asking
their doctors or midwives for early access to combined ultrasound and blood
He stressed that having
an ultrasound test on its own is no longer sufficient and it should be
combined with blood tests before the 13th week of pregnancy to test for
Prof Malone stressed that
there are technical challenges for health prpfessionals in performing the
special ultrasounds involved properly, as measurements that are off by
even a fraction
can give very inaccurate results.
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