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Key messages from the NHS Fetal Anomaly Screening Programme:
- All pregnant women should be offered screening for Down's syndrome.
- Women should understand that it is their choice to embark on screening
for Down's syndrome.
- Tests should meet a detection rate (DR) of more than 90%, for a screen
positive rate (SPR) of less than 2% (of affected pregnancies) for England
for those undergoing combined screening.
- Tests should meet a detection rate (DR) of more than 75%, for a screen
positive rate (SPR) of less than 3% (of affected pregnancies) for England
for those undergoing quadruple screening.
- Screening for Down's syndrome can be undertaken from 10 weeks + 0 days
to 20 weeks + 0 days of pregnancy.
- Screening for Down's syndrome should be performed by the end of the
first trimester (14 weeks and 1 day), but provision should be made to allow
later screening (which could be as late as 20 weeks 0 days) for women booking
later in pregnancy.
- The overall timeline for pregnancy chromosomal screening (test) and
the laboratory risk calculation is from 10 weeks + 0 days to 20 weeks +
0 days of pregnancy.
- When it is not possible to measure nuchal translucency as part of combined
screening, owing to fetal position or raised body mass index, women should
be offered the quadruple test.
- The following tests meet current standards:
- From 10 weeks + 0 days to 14 weeks + 1 day the combined test (maternal
serum - hCG and PAPP-A and nuchal translucency scan) is the recommended
- From 14 weeks + 2 days to 20 weeks + 0 days, the quadruple test
(maternal serum - hCG, AFP, uE3, inhibin A)) for those presenting later
is the recommended screening strategy.
- GP's should receive an annual report of local screening programmes
Information about screening for Down's syndrome should be given to pregnant
women at the first contact with a healthcare professional. This will provide
the opportunity for further discussion before embarking on screening. Specific
information should include:
- the nature of the screening test offered locally, how it is done, and
timing of the test;
- the possible meaning and implication of the test results as well as
potential significant clinical and emotional consequences;
- the decisions that might need to be made at each point along the pathway
and their consequences;
- how and when the results will be given;
- the screening pathway for Down's syndrome screening, including how the
pathway might change for those with both lower risk and higher risk Down's
syndrome screening results, and for women who do not opt to have screening;
- the screening pathway for fetal anomaly screening, including those women
who do not opt to have screening;
- the possibility that screening can provide information about other conditions;
- the fact that screening does not provide a definitive diagnosis;
- information about chorionic villus sampling and amniocentesis;
- that confirmatory/repeat testing may occasionally be required;
- balanced and accurate information about the various conditions being
- balanced and accurate information about Down's syndrome.
- if a pregnant woman receives a screen-positive result for Down's syndrome,
she should have rapid access to appropriate counselling by trained staff.
- routine anomaly scan (at 18 weeks 0 days to 20 weeks 6 days) should not
be routinely used for Down's syndrome screening using soft markers.
- the presence two or more isolated soft marker, with the exception of increased
nuchal fold, on the routine anomaly scan, should not be used to adjust the
a priori risk for Down's syndrome.
- the presence of an increased nuchal fold (6 millimetres or above) or two
or more soft markers on the routine anomaly scan should prompt the offer of
a referral to a fetal medicine specialist or an appropriate healthcare professional
with a special interest in fetal medicine
The Fetal Anomaly screening programme has working groups looking at standards,
and education and training. Further information on all above aspects is available
Note that NICE states (1) a different timeline for combined and quadruple tests
- the 'combined test' (nuchal translucency, beta-human chorionic gonadotrophin,
pregnancy-associated plasma protein-A) should be offered to screen for Down's
syndrome between 11 weeks 0 days and 13 weeks 6 days. For women who book later
in pregnancy the most clinically and cost-effective serum screening test (triple
or quadruple test) should be offered between 15 weeks 0 days and 20 weeks
- NICE (March 2016). Antenatal
care for uncomplicated pregnancies
- NHS Fetal Anomaly Screening Programme. Antenatal screening - working standards
for Down's syndrome screening 2007. NHS FASP; 2007.
- NHS Fetal Anomaly Screening Programme. Consent standards for screening
fetal anomalies during pregnancy 2007. NHS FASP; 2007.
- NHS Fetal Anomaly Screening Programme. NHS fetal Anomaly screening programme
- screening for Down's syndrome: UK NSC Policy recommendations 2007-2010:
Model of Best Practice. Department of Health; 2008.
- Kirwan D, NHS FASP. 18+0 to 20+6 weeks fetal anomaly scan -National standards
and guidance for England 2010. Exeter, England: NHS Fetal Anomaly Screening
Last reviewed 01/2018