ovarian cancer Stages and Treatment

 Antenatal screening for Down Syndrome 

Down syndrome is a chromosomal abnormality in which there is an extra copy of

chromosome number 21 (often known as trisomy 21).

1 Characteristic features of Down syndrome include macroglossia, epicanthic folds,

upslanting palpebral fissures and a single transverse palmar crease. Individuals

with Down syndrome have a higher incidence of congenital heart defects, gastro-

oesophageal reflux, recurrent ear infections and thyroid problems.

1 Down syndrome can be diagnosed either before birth (antenatally) or after birth.

1 The latest NICE guidelines recommend that all pregnant women should be offered

screening for Down syndrome.

1 There are two different types of tests that can be done in pregnancy – a screening

test and a diagnostic test.

! Screening test – looks at the chance of a baby being born with Down syndrome

in the current pregnancy.

! Diagnostic test – amniocentesis or chorionic villus sampling is used to give a

definite diagnosis as to whether or not the fetus has Down syndrome. Usually

only done if the screening test indicates a high chance of Down syndrome

(usually >1/250 risk).

1 Screening tests used include:

! The combined test is the one which NICE currently recommends. This includes

a nuchal translucency scan (measures the size of the nuchal pad at the nape

of the fetal neck) and blood tests for serum PAPP-A and b-hCG (undertaken

between 11 weeks and 13 weeks+6).

! Amniocentesis – a sample of amniotic fluid is taken from the amniotic sac using

a fine needle. This is normally done at 15 weeks of gestation and carries an

additional 1% risk of miscarriage.

! CVS – a small sample of tissue is taken from part of the placenta called the

chorionic villi. Normally done at 11+0–13+6 weeks of gestation (RCOG, 2010:

Green-top guideline 8: Amniocentesis and chorionic villus sampling) and carries

an approximately 2% risk of miscarriage.

Data gathering

Open question

1 “What do you know about Down syndrome and the antenatal screening tests available?”.

Focused/closed questions

HPC: “Is this your first pregnancy?”

If not, any problems in previous pregnancies? Miscarriages? TOP?

 “Have you had Down screening in previous pregnancies? Any concerns?”

SH: “Who lives with you at home?” Occupation? Support?

FH: Does anyone in the family have Down syndrome?

ICE: “Do you have concerns about the risk of Down syndrome?”

“Do you know anyone with Down syndrome?”

Examination: 

• BP

• Routine antenatal examination

Clinical management 

Investigations

1 Screening tests (see www.patient.co.uk article ‘Antenatal Screening for Down’s

Syndrome’ for further details).

•  Amniocentesis.
•  CVS.

Explanation to patient

Down syndrome is a genetic disorder where a person inherits an extra copy of one

chromosome. The additional genetic material changes the finely tuned balance

of the body, resulting in characteristic physical features and affects the normal

physical development.

Management

•  Give patient information leaflet.
•  Follow up after the screening/diagnostic tests.
•  Refer to obstetrician and geneticist if Down syndrome confirmed antenatally.