You may have been offered a test because you have:

• Had a high-chance/risk screening test for
  One of the most common chromosomal abnormalities in humans. All chromosomes come in pairs, but Down’s Syndrome is caused by an extra copy of chromosome 21.
  Down’s
  ,
  All chromosomes come in pairs, but Edward’s Syndrome is caused by an extra copy of chromosome 18.
  Edward’s
  or
  All chromosomes come in pairs, but Pataus’s Syndrome is caused by an extra copy of chromosome 13.
  Patau’s Syndrome
• You know that your family has an inherited disorder such as
  Sickle cell trait and disease is an inherited condition. Within each red blood cell is a structure called haemoglobin that carries oxygen (for energy) to the body’s cells. In sickle cell the structure of the haemoglobin is abnormal.
  Sickle Cell
  ,
  Thalassemia is a group of inherited blood disorders passed down through families. In thalassemia the body produces no or too little haemoglobin that results in anemia (tired, short of breath and pale). The most serious cases can be life threatening.
  thalassemia
  ,
  Cystic Fibrosis (CF) is an inherited condition where the lungs and digestive system become clogged with thick, sticky mucus.
  cystic fibrosis
  or
  Muscular Dystrophy (MD) refers to a group of inherited conditions that affect the ability of muscles to function.
  muscular dystrophy
• Structural abnormalities in the fetus have been found on ultrasound scan
• You have had a previous pregnancy/baby affected by a genetic condition

An amniocentesis can be performed from 15 weeks’ of pregnancy.

You are first scanned to check the baby, the amount of amniotic fluid around the baby and the location of your

Following the scan, your abdomen is cleaned with antiseptic. The doctor will insert the needle through your abdomen and womb, using ultrasound to guide the direction of the needle. A small amount of fluid is withdrawn via a syringe (approximately 15-20mls of fluid).

After taking the needle out, the doctor can show you the baby’s heart beat.

The test normally takes around 5-10 minutes to perform and once done you will be taken to a quiet area to relax until you feel able to go home, usually about 30 minutes later.

Occasionally, for fewer than 7 in every 100 women, we cannot take enough fluid at the first attempt and have to re-insert the needle. This is usually due to the position of your baby.

If a second attempt fails, we will offer an appointment to have the amniocentesis again on another day.

Initial amniocentesis results are usually available in around 3-5 days. This result (the ‘PCR’ rapid test) will just identify abnormalities of chromosomes 21 (Down’s Syndrome), 18 (Edward’s Syndrome) and 13 (Patau’s Syndrome), which are the commonest chromosomal problems. Testing for other genetic conditions may take up to 2 weeks.