Antenatal tests

There are many antenatal tests that you will take during your pregnancy, some are routine, and some can be 'extra' to ease concerns or provide more information if you are a higher risk.

Ultrasound Scans

The first scan that you have is between 10 – 13 weeks at your booking appointment, to check that the dates of the pregnancy correspond with the baby’s size.

You then have a scan at 20 weeks, to check for physical defects and spina bifida. They will see that the baby’s head, body and organs are alright. It is also to look at the position of the placenta and the amount of fluid around the baby. You are asked to have a full bladder for ultrasound scans, then they put cold gel on your tummy – brace yourself!

Blood Tests

At around 16 weeks you will also be given some blood tests. These are to test for:

  • What blood group you are and whether you are rhesus (Rh) positive or Rh negative.
  • Anaemia
  • Hepatitis B, HIV and syphilis
  • If you are immune to german measles (rubella)

You may be offered a blood test at 11+ weeks called Alpha-Fetoprotein Test, to see how high a risk you have of having a baby with Down’s syndrome or spina bifida. Some hospitals offer nuchal fold scan instead (see below).

Or the Bart’s triple test at 16 weeks looks at the blood chemical levels to assess the risk of Down’s syndrome or spina bifida.

Nuchal Fold Scan

An ultrasound carried out at 11 – 14 weeks. It measures the fluid at the back of the baby’s neck. It tests for Down’s syndrome and is usually offered instead of blood tests as it gives more accurate results. If there is thought to be a substantial risk, then an amniocentesis is offered.

Amniocentesis

Usually offered at 15 – 19 weeks of pregnancy. A fine needle is used to drain a small amount of fluid from around the baby. This fluid is then tested for genetic disorders, Down’s syndrome and cystic fibrosis. It carries a small risk of miscarriage. Therefore it is usually offered to mothers who are classed as being higher risk, such as the over 35’s or have tests indicating that this may be the case.

Chorionic Villus Sampling (CVS)

Chorionic Villus Sampling is where a sample of the chorionic villi, which are found on the placenta, is taken. The test can be carried out at 10 – 12 weeks and results can be obtained quicker than with amniocentesis. It is used to test for Down’s syndrome and other chromosomal disorders but not neural tube disorders. It carries a small risk of miscarriage, about 1 -2%.

Urine

Tested regularly to check for protein being present. This can be a sign of pre-eclampsia which can be dangerous to both mum and baby.

Cordiocentesis

A test where blood is extracted from the umbilical cord to diagnose birth defects. It is offered to those thought to be at a higher risk.