Tests in pregnancy

Routine tests

Why your blood pressure and urine is checked

You might be at increased risk of a blood pressure problem

Some women and pregnant people, with factors in their medical or obstetric history are at slightly higher risk of a blood pressure problem during pregnancy.

National guidance recommends that to reduce this likelihood, these women and pregnant people should take Aspirin daily from 12 weeks until the birth of the baby or the development of a blood pressure problem.

NHS - Aspirin in Pregnancy

Pre-eclampsia - Essential Information

Urine test

At your routine antenatal appointments you will be asked to provide a clean, fresh sample of urine. Having certain substances in your urine can give your midwife an indication of early signs of conditions which may cause problems for you and your baby.

What will my urine be tested for?

Mid-stream urine

Assessing your baby's growth (symphysis fundal height)

Your symphysis fundal height (SFH) will be measured from 26-28 weeks of pregnancy.

The measurements are taken with a centimetre paper tape measure, from the top of the uterus to the top of the symphysis (pubic bone).

The measurement is then plotted on the graph in your notes.

Not all women and pregnant people will have their abdomen measured, certain women will need a regular ultrasound from 28 week as they are at increased risk of having a small baby or the measurement is less reliable.

Examples are:

Your abdomen will not be measured if:
You have a multiple pregnancy
have a BMI over 35
increased fluid around your baby
large fibroids

Check with your midwife how your baby's growth will be assessed.

Ultrasound scans

You will be offered two routine scans in the first half of your pregnancy (usually by 21 weeks). As with any tests, it is up to you whether you want any scans to be performed in your pregnancy.

A pregnancy scan, or ultrasound scans uses high-frequency sound wavs to create a moving image of your babby, his internal organs and your placenta. It is safe for mother and baby to have ultrasound scans.

Dating Scans

The main reason for a dating scan is to check how advanced the pregnancy is and therefore when the baby is due. Measuring the baby is more accurate than dating by the last menstrual period.

It is also an opportunity to check the baby is alive and developing as expected, and check for twins. If you have accepted the offer of the Combined Test, the dating of the pregnancy is also part of this test.

Occasionally, if the baby is in an awkward position, an internal scan may be carried out, using a vaginal probe.

See Healthtalk - My 12 week scan, where you can see and hear a real life experiences of having a dating scan.

Detailed Scan/ Anomaly Scan

The purpose is to check the baby is developing as expected and to look for any serious abnormalities, such as heart problems, spina bifida or chromosomal conditions such as Edwards' syndrome and Patau's syndrome.

The scan can identify potential problems with the baby that may benefit from early intervention following delivery and in some cases interventions that can be carried out during pregnancy.

It is really important that you read the booklets available online linked below, which gives detailed information about what we are looking for.

Growth Scan

A growth scan is to check how well your baby is growing. Your midwife or obstetrician may suggest that you have a scan if he/she thinks your baby is smaller or larger than expected for your stage of pregnancy or because you are increased risk of having a small baby. This may be picked up when the size of you 'bump' is checked during one of your antenatal appointments.

The sonographer will check your baby's size by measuring:

The circumference of your baby's head (HC).

The circumference of your baby's tummy (AC).

The length of your baby's thigh bone (femur) (FL).

The depth of the amniotic fluid around your baby.

If the measurements are all within normal limits, your baby is likely to be of average size.

A second scan may be recommended 2-4 weeks later, because babies grow at uneven rates. A series of scans track your baby's growth, so are more useful than a single scan.

Piecing together information from the scan can give a picture of how your baby is doing. If your baby has an average head size and a small tummy, this may simply mean that you have a small, healthy baby.

Occasionally, though, this can be a sign that your baby is not growing as expected. The scan may also show that the amount of amniotic fluid around the baby is low. If this happens you will see one of our obstetricians and a plan made for pregnancy.

If your baby is smaller than expected, your sonographer will perform a Doppler scan. This checks how well the placenta is working by measuring the flow of blood between the placenta and your baby.

Some areas use customised growth charts that take into account your size and ethnicity, which may influence how big your baby grows. These charts are produced in the early half of pregnancy

Increased BMI and your scans

Can I bring my family or friends to my scan?

Yes. Ultrasound scans can sometimes find problems with the baby. You may like someone to come with you to the scan appointment.

Due to the small size of the room, we allow only one person into the scan room with you.

Children often get very bored during a scan. We ask that you do not allow children to attend scans, as we do not have childcare.

Remember, an ultrasound scan is an important medical examination and it is treated in the same way as any other hospital investigation.

Can I have a picture of my baby?

Useful links

Screening tests for you and your baby

The first half of pregnancy is a time when various tests are offered to check for potential problems. Screening tests are used to find out if you are at higher risk of a health problem.

gov.uk - Screening tests for you and your baby

Open

To contact the antenatal screening team

The tests below are the ones that we routinely offer.

Don't hesitate to ask your midwife, GP or Obstetrician what each test means for you.

Blood group and antibodies

At your 'Booking appointment' you will be offered a test to find out what blood group you are (A, B, AB or O) and also your rhesus status (positive or negative).

Your rhesus factor is fixed by your genes. If you're rhesus positive (RhD positive), it means that a protein (D antigen) is found on the surface of your red blood cells. If you do not have the D antigen, you will be rhesus negative (RhD negative).

Rhesus status only matters if you are a rhesus-negative mum who is carrying a rhesus-positive baby. Your child will have inherited her rhesus-positive status from her rhesus-positive dad.

If you are RhD negative you will be offered a repeat test to check for antibodies between 28 - 32 weeks of pregnancy.

Most people are rhesus positive.

I'm rhesus negative, what does this mean?

If some of your baby's blood enters your bloodstream, your immune system may react to the D antigen in your baby's blood. It will be treated as a foreign invader and your body will produce antibodies against it. This is known as a sensitising event or being sensitised.

Sensitising is not usually harmful if it is your first pregnancy. But it can cause problems if you become pregnant again with another rhesus-positive baby. The antibodies that your body made in your first pregnancy can quickly multiply, cross the placenta and attack the blood cells of your baby.

The good news is that, because of routine injections of a substance called anti-D immunoglobulin (anti-D) to guard against the harmful effects of antibodies, complications are rare. However, if you are not treated with anti-D, the immune response in your second pregnancy will be stronger than the first pregnancy and can cause rhesus disease in your baby. Your antibodies start to attack your baby's blood cells during pregnancy and can carry on attacking them for a few months after the birth.

After she's born, your baby's liver won't be able to cope with the volume of blood cells that need breaking down. She may then become jaundiced, which is called haemolytic disease of the foetus and newborn (HDFN), or haemolytic disease of the newborn (HDN).

Don't worry. Your midwife will take a sample of blood at your booking appointment which will tell her if you're rhesus negative. You'll then be offered anti-D injections as part of your antenatal care.

D negative mother’s blood test to check her unborn baby’s blood group

Blood Groups and Red Blood Cell Antibodies in Pregnancy Information

Hepatitis B Screening

Hepatitis B is a virus which affects the liver. It often doesn't cause any obvious symptoms in adults and typically passes in a few months without treatment. Many people with hepatitis B won't experience any symptoms and may fight off the virus without realising they had it. Although most women do not have any pregnancy complications as a result of HBV infection, it is still a good idea to be seen by a specialist.

I've been told I'm hepatitis B positive

Following your blood test, should you have a positive screen test result you will be contacted by a member of the antenatal screening team.

The specialist midwife will talk through the result and arrange to see you for a 'face to face' appointment within 10 days of calling you. At this appointment you will also be seen by a viral liver specialist nurse.

You will need to under the care of an obstetrician and a specialist team skilled at managing hepatitis B infection.

Your will have additional laboratory testing to see how much of the virus is carrying and whether the infection is current or past. After the birth of your baby you will continue to be cared for by the Doctors specialising in liver disease.

Hepatitis B: a guide to your care

How do I protect my baby from Hepatitis B

If you are a carrier, or have become infected during pregnancy, you will be advised to have your baby immunised at birth.

If a baby does not receive these drugs in time, then there is a greater than 90% possibility that he or she will become chronically infected. There is no second chance!

Protecting your baby against hepatitis b with the hepatitis b vaccine

Children's Liver Disease Foundation - UK charity CLDF takes action against the effects of childhood liver disease, providing information, emotional support, research funds and a voice for all affected.

HIV

Any woman can be at risk from having HIV. HIV infection in young children most commonly arises as a result of mother-to-child transmission (MTCT). It is thought that only 1.5-2% of MTCT occurs across the placenta during pregnancy. The vast majority occur when the virus is passed to the baby during pregnancy, at birth or breastfeeding.

All pregnant women are recommended screening for HIV infection, syphilis, hepatitis B in every pregnancy at their booking antenatal visit. If a woman declines an HIV test, this will usually be documented in your maternity notes. The test will be re-offered again at around 28 weeks.

A negative maternal HIV test at booking does not preclude neonatal infection - maternal infection can occur at any time during pregnancy and lactation. This is well-documented in countries with a high prevalence of HIV and has been seen in the UK.

Treatment given in pregnancy can greatly reduce the risk of infection being passed from mother to child.

You can request testing for HIV at any time if you change your sexual partner or think you are at risk.

I'm HIV positive

Treatment given in pregnancy can greatly reduce the risk of infection being passed from mother to child.

If you are HIV positive you will be under the care of a Consultant Obstetrician and be cared for by a specialist team of staff who are experienced and skilled in caring for women with HIV.

You can request testing for HIV at any time if you change your sexual partner or think you are at risk

HIV positive screening result

What everyone should know

Useful Links

British HIV Association

Charities:

National AIDS Trust 

is dedicated to transforming the UK's response to HIV. They champion the rights of people living with HIV and campaign for change-shaping attitudes, challenging injustice, and changing lives.

Terence Higgins Trust

is at the forefront of the fight against HIV and improving the nation's sexual health.

Useful Links

British HIV Association

Charities:

National AIDS Trust - is dedicated to transforming the UK's response to HIV. They champion the rights of people living with HIV and campaign for change-shaping attitudes, challenging injustice, and changing lives.

Terence Higgins Trust - is at the forefront of the fight against HIV and improving the nation's sexual health.

Sexually Transmitted Infections

Screening for Down's [T21], Edwards' [T18] and Patau's [T13] syndromes

The Combined Test

This test involved having a bloods test and an ultrasound scan. An ultrasound scan is performed between 11 weeks and 2 days and 14 weeks and 1 day, to measure the fluid at the back of the baby's neck (nuchal translucency). You will usually have blood taken at the same time. The blood test is taken from you to measure levels of substances naturally found in the blood. A computer programme is used to calculate your individual risk.

You will be given two separate risk results - one for Down's and one for Edwards' and Patau's syndrome.

Results

If you have a 'lower risk' result, you will be sent a letter.

If you have an 'increased risk' result, you will be contacted by one of the Midwives from the Antenatal Screening Team. You will be offered a diagnostic test which can definitely tell you if your baby has Down's, Edwards' or Patau's syndrome.

The Quadruple Test

This is available if you are too far on in your pregnancy to have the combined test. This test is for Down's syndrome only. A blood sample is taken between 14 weeks and 2 days and 20 weeks. A computer programme works out a risk for you.

Please note we do not offer to take the test beyond 20 weeks pregnancy.

Results

If you have a 'lower risk' result, you will be sent a letter.

If you have an 'increased risk' result, you will be contacted by one of the Midwives from the Antenatal Screening Team. You will be offered a diagnostic test which can definitely tell you if your baby has Down's, Edwards' or Patau's syndrome.

RUH Antenatal and Newborn Screening Information

Antenatal Results and Choices - Support through antenatal screening and its consequences

Sickle Cell and Thalassaemia (unusual haemoglobin)

Sickle Cell and Thalassaemia are blood disorders which affect haemoglobin and can be passed from parent to child. All women will be offered a test for thalassaemia. You will not always be offered the test for sickle cell. Your midwife will complete a questionnaire, that will be informed by asking you about where your family and the family of the father of the baby come from.

Sickle Cell Disease Information

Sickle Cell Carrier

Thalassaemia (unusual haemoglobin)

Being a carrier of an unusual haemoglobin will not cause you any health problems.

The reason why you need to understand about being a carrier of an unusual haemoglobin is because you could pass the gene on to your children.

The following leaflets tell you about certain unusual haemoglobins.

Useful Links

UK Thalassaemia Society 

Sickle Cell Society 

Glucose Tolerance Test (GTT)

Useful links

Group B Streptococcus (GBS)

You might have already heard of Group B Streptococcus (GBS) or you have been told that a recent vaginal or rectal swab or urine test has found GBS.

We do not routinely screen pregnant women for GBS.

GBS is carried by around a quarter of healthy adult women. Carriage causes no symptoms or harm to Mum.

GBS is a bacterium that can cause serious illness in people of all ages, with the infections especially severe in newborn babies.

Fortunately, the vast majority of these infections can be prevented, simply and safely, when Mums carrying group B Strep are offered antibiotics in labour.

Will I be offered antibiotics?

You will be offered antibiotics if:

Group B Strep has been identified during the current pregnancy (from urine tests)

a previous baby was diagnosed with group B Strep infection, or

you have a fever in labour or other signs and symptoms of infection

You may be offered antibiotics in labour if labour starts prematurely (before 37 weeks), if your waters break before labour starts, or if your waters have been broken for more than 12 hours when the baby is born. Your baby may need some extra observations for a period after birth.

Screening for GBS

Tests in Pregnancy

Menu

Routine tests

Urine test

Assessing your baby's growth (symphysis fundal height)

Ultrasound scans

Useful links

Healthtalkonline

Healthtalkonline

NHS Choices

NHS Choices

Screening tests for you and your baby

gov.uk - Screening tests for you and your baby

gov.uk - Screening tests for you and your baby

To contact the antenatal screening team

Useful links

Antenatal Results and Choices

Antenatal Results and Choices

NHS Choices

NHS Choices

Group B Streptococcus (GBS)