Diagnostic testing and follow-up
This section describes the diagnostic tests that may be offered to you during pregnancy and the ways that follow-up may be arranged. You should read this alongside specific information about individual screening tests in earlier sections.
These tests are offered to women who have a 'high chance' result from screening for sickle cell disorder, thalassaemia or Down's syndrome, and in some other circumstances.
Chorionic villus sampling (CVS)
CVS can be done from eleven weeks of pregnancy and is usually only offered in a specialist centre. With the help of an ultrasound scan, an obstetrician will guide a fine needle through your abdomen or, in rare cases, through your cervix to take a small sample of tissue from the placenta. They analyse this in the laboratory and count the baby's chromosomes. For around two in every one hundred samples, CVS does not produce a clear result. If this happens you may be offered further tests.
Amniocentesis can be carried out after fifteen weeks of pregnancy. It usually takes about ten minutes. An ultrasound scan will be performed to check the position of your baby in the womb. An obstetrician will then insert a fine needle through your abdomen into your womb. They use the needle to take a sample of fluid surrounding the baby (called 'amniotic fluid'). This fluid contains cells from the baby which will be examined later at the laboratory. The baby's chromosomes will be counted as well. For around one in every one hundred samples the results are not clear. If this happens you may be offered further tests.
Are these tests painful?
While many women find the procedures uncomfortable, they shouldn't be painful. For a day or two afterwards you may have some discomfort in your lower abdomen, this is normal and you can take paracetamol to relieve the discomfort. You should take things easy and avoid strenuous exercise. If discomfort persists, contact your midwife.
How safe are these diagnostic tests?
They are not completely safe and this is why they are not offered to everybody.
For every one hundred women who have CVS, one or two will miscarry. For every one hundred women who have amniocentesis, one will miscarry. If you would like to know more about the miscarriage rates after CVS or amniocentesis in your hospital, ask the health professional taking care of you.
What happens if the diagnostic test finds a problem?
In most cases, follow-up testing finds a healthy baby. If the test finds a chromosome variation, the health professional will talk to you about it and the options that you have. You will be able to choose what you feel is best for you. Some people may decide to continue with the pregnancy while others will feel that termination of pregnancy is right for them. Termination is when a pregnancy is ended either by taking medicines or by surgery.
There will be no pressure to influence you in your decision. The hospital staff will provide you with help and support whatever you decide.
Referral to the foetal medicine team
If you are offered further tests, the health professional taking care of you will give you more information and may refer you to the foetal medicine team. This is a team that includes a specialist doctor, midwife and other health professionals. Members of this team may offer you further tests and provide further information and advice about any health problems you or your baby might have. This could be in another hospital and they will usually give you an appointment within a few days.
In most cases, further tests don't find any health problems. However, they can cause great worry for parents and for some people this worry can continue throughout the rest of their pregnancy. You may want to ask questions and talk about these concerns with your own midwife, doctor or consultant.
Other sources of information and support are available.
If a definite health problem is found, what happens next?
What happens next will depend on what the condition is and how serious it is. Some problems may turn out not to be serious and others will get better on their own. You may be offered further scans throughout the pregnancy to monitor these problems.
If the health problem is serious, the health professional caring for you will discuss your options with you, which may include having a termination or preparing for the birth of a seriously ill baby. If you need to make any decisions, your midwife and the hospital team will give you time, support and information.
Our further information section lists organisations who can offer advice and support.