Amniocentesis

Question 1

An amniocentesis is…

Answer 1

Anamniocentesisis a procedure used to sample a small amount of amniotic fluid from around the fetus.

Question 2

In amniocentesis, it is not the fluid itself which is of use, but…

Answer 2

It is not the fluid itself which is of use, but thefetal cellsthat are present in the fluid.

Question 3

Describe the amniocentesis procedure.

Answer 3

• a local anaestheticis used to decrease pain for the mother.
• Underultrasound guidance, a needle is passed through the mother’s abdominal wall and into the amniotic sac.
  
  • The needle should not pass through the placenta unless absolutely necessary.
  • A small amount of amniotic fluid is taken, and fetal cells are sent forkaryotypingand/or PCR

Question 4

In amniocentesis, a small amount of amniotic fluid is taken, and fetal cells are sent for…

Answer 4

A small amount of amniotic fluid is taken, and fetal cells are sent forkaryotypingand/or PCR.

Question 5

The potential complications of an amniocentesis are:
[six points]:

Answer 5

• 0.5% risk of miscarriage (RCOG). The risk is higher in a multiple pregnancy
• False reassurance – a “normal” result may make women feel their baby will be born completely healthy when this may not be the case.
• Risk of infection, as with most surgical procedures
• Pain from the procedure
• Rhesus sensitisation (seehere)
• Increased risk of club foot — talipes equinovarus

Question 6

The fetal cells that are obtained from amniocentesis can be tested for various chromosomal conditions, such as…

Answer 6

The fetal cells that are obtained can be tested for various chromosomal conditions, such asDown’s syndrome, Edward’s syndrome and/or Patau’s syndrome.

Question 7

[RCOG] Women should be informed that the additional risk of miscarriage following amniocentesis or CVS performed by an appropriately trained operator is likely to be….

Answer 7

Royal College of Obstetrics & Gynaecology

Women should be informed that the additional risk of miscarriage following amniocentesis or CVS performed by an appropriately trained operator is likely to be below 0.5%.

Question 7

The most common indication for amniocentesis is…

Answer 7

The most common indication for amniocentesis is a “high risk” result from afirst trimester screening test, or a previous pregnancy affected by a genetic condition.

Question 8

Amniocentesis should not be performed prior to…

Answer 8

Amniocentesis should not be performed prior to 15+0 weeks’ gestation.

Question 9

[RCOG Guideline] Women with multiple pregnancies should be informed that the additional risk of miscarriage for twin pregnancy following CVS or amniocentesis performed by an appropriately trained operator is …

Answer 9

Women with multiple pregnancies should be informed that the additional risk of miscarriage for twin pregnancy following CVS or amniocentesis performed by an appropriately trained operator is around 1%.

Question 10

Screening results for … should be reviewed when amniocentesis is considered and … should be discussed.

Answer 10

Screening results for blood borne viruses, viral load and antigen test results should be reviewed when an invasive test is considered and individualised risk of viral transmission should be discussed.

Question 11

The main alternative to amniocentesis is….

Answer 11

The main alternative to amniocentesis ischorionic villus sampling.