Investigations during pregnancy

Routine investigations

There are a number of investigations/tests which may be offered to you during your pregnancy. These will be explained and your consent sought before any test is done. If you want further information on any of the investigations please ask your GP or midwife.

Blood tests

All women are offered blood tests at your booking visit. The blood will be tested for:

Full blood count - to check for anaemia and signs of infection

Blood group - to check for rhesus factor and antibodies (These two tests will be repeated during the pregnancy)

Blood glucose - to check if you are at risk of gestational diabetes

Rubella status - this indicates whether or not you are protected against German measles ; if you are not we will offer you immunisation after birth

Screening for syphilis - we can treat any woman found to have syphilis and therefore protect the baby and ensure you are treated before it makes you unwell

Hepatitis B - we can treat the baby and any family members to reduce their risk of getting hepatitis B

HIV - being aware if you have HIV enables us to treat you earlier and therefore keep you well and also reduce the chance of transferring HIV to your baby from 25% to less than 1%

The results of these tests will be given to you as soon as possible.

Diagnostic tests

CVS (Chorionic Villus Sampling)

A CVS is offered to women who have a high risk combined result, or if there are other reasons where it is thought to be beneficial to have a diagnostic test.

It is not offered to all women as there is about a 1% chance of miscarriage because of the procedure. 

It is usually performed at 11-14 weeks.

You may be referred to either to the Fetal Medicine Unit at St Georges Hospital or the Harris Birthright Trust at Kings College Hospital to have this done, after counselling with a midwife or obstetrician.

Amniocentesis

Amniocentesis is offered to women with a positive quadruple screen, if too late for CVS or where there is a clinical need. It carries about a 1% chance of miscarriage.

Screening Tests

Combined Screening - a test performed to determine the risk / chance of a pregnancy being affected by Down's syndrome.

The test combines the results of a blood test with the nuchal translucency measurement from the ultrasound scan and the maternal age to calculate the risk.

The combined test is performed between approximately 10 weeks and 14 weeks of pregnancy.
 
Quadruple Test - a test performed to determine the risk / chance of a pregnancy being affected by Down's syndrome.

This test is performed between 14 weeks and 22 weeks of pregnancy and is provided for women who book later in pregnancy and are too late for combined screening.

The test combines the results of a blood test with maternal age to calculate the risk.

Results for both tests are sent out by first class post usually 24-48 hours after the blood test.

Women whose test results demonstrate a higher chance of the pregnancy being affected by Down's syndrome are also contacted by telephone if possible.

If the combined test or quadruple test identifies a higher chance of the pregnancy being affected by Down's syndrome, the Screening Coordinator will provide information about diagnostic tests.