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Antenatal Screening
Mehreen Yousaf
GP STS
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Antenatal screening
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Sickle Cell and Thalassaemia
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Infectious Diseases
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Downs syndrome
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Summary
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Informed Choice
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Screening is a choice and it is important that women and
their families are given unbiased, balanced information, in a
timely manner and in a format they can understand to help
them make that choice
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The decision to take up or decline the offer of screening
should be recorded
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Sickle Cell & Thalassaemia
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Offer all pregnant women screening for sickle cell and
thalassaemia by 8-10 weeks of pregnancy
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If the pregnant woman is identified as, or known to be a carrier –
offer screening to the baby’s father as soon as possible
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Observing local policy, base screening on the Family Origin
Questionnaire and blood test results
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Testing can be carried out pre conceptually on request
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All babies can be screened for sickle cell disease on the
newborn blood spot
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sct.screening.nhs.uk/
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Infectious Diseases
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Screening for HIV, Hepatitis B, Syphilis and Rubella susceptibility should
be offered to all pregnant women, early in pregnancy
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All women who have, or who are already known to have positive screen
results for HIV, Hepatitis B or Syphilis are referred for appropriate
specialist care in line with current programme standards
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Women who are susceptible to Rubella, should be offered MMR
immunisation for future pregnancies, and if the offer is accepted, they
should receive their first dose before discharge by maternity services,
and the second dose should be offered by the GP
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Babies that are born to Hepatitis B positive mothers, should be
vaccinated within 24 hours, and at 1, 2 and 12 months of age
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infectiousdiseases.screening.nhs.uk/
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Fetal Anomaly: Down’s syndrome
(Trisomy 21)
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All women in England should be offered a screening test for Trisomy 21
that meets agreed national standards
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Women should be offered information in a timely manner to help them
decide if they want screening or not
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The aim of this screening programme is to identify those women at a
higher risk of having a baby with Down's syndrome and offer them
diagnostic testing
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1st trimester combined screening is the recommended screening
strategy for Trisomy 21. The scan to measure the nuchal translucency
and crown rump length can be performed from 11+2 to 14+1 weeks
gestation and the corresponding serum sample from 10+0 to 14+1
weeks gestation
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The serum screen measures free beta-hCG (human chorionic
gonadotrophin) and Pregnancy-associated plasma protein A (PAPP-A)
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The quadruple test can be taken between 14+2 to 20+0
weeks gestation. It is the screening strategy of choice in the
2nd trimester for women booking later in pregnancy or when
it is not possible to measure the nuchal translucency
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This measures free beta-hCG, alpha fetoprotein (AFP),
inhibin-A and unconjugated estriol (uE3)
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The chance of the fetus having Down's syndrome is
calculated using software that takes into account maternal
factors such as age, weight and family origin, gestation of the
pregnancy.
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The screening test is positive if this probability is equal to, or
greater than, a nationally agreed cut-off level (1 in 150)
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These women are then offered diagnostic testing.
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Questions?