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Further testing during pregnancy

If you're expecting a baby and you and your partner are both carriers of unusual haemoglobin, you may choose to have further tests to find out if and how the baby is affected.

Not all haemoglobin disorders cause major problems, but some - including the most common, sickle cell disease and thalassaemia  major - are serious conditions that need lifelong treatment and support.

The main tests to find out if your baby is affected and what kind of disorder he or she has are amniocentesis and chorionic villus sampling, collectively known as Prenatal Diagnosis (PND).

  • Chorionic villus sampling (CVS) takes cells from the placenta. This test can be done from the 11th week of pregnancy. It carries a slightly higher risk than amniocentesis.
  • Amniocentesis takes a sample of fluid from around the baby. The fluid contains some of the baby's cells, which are tested for genetic problems. There is a slight risk of miscarriage (about 1 in 100) resulting from this test. Amniocentesis is usually done from the 16th - 20th week of pregnancy.
  • The test results can take up to 18 days.

Later on in pregnancy, blood can also be taken directly from the baby to test for unusual haemoglobin.

Having tests and waiting for the results can be stressful and worrying. You will be offered support throughout, and help with:

  • understanding the test result 
  • making decisions about carrying on with the pregnancy or about termination in line with your beliefs and values.
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