Pregnancy Guide
NHS Choices

Routine Checks and Tests

Routine Checks and Tests

Antenatal checks and tests

During your pregnancy, you'll be offered a range of tests, including blood tests and ultrasound scans. These tests are designed to check and assess the development and wellbeing of you and your baby, and screen for particular conditions.

You don't have to have any of the tests. However, it's important to understand the purpose of all tests so that you can make an informed decision about whether to have them. Discuss this with your maternity team. You'll be given written information about the screening tests on offer. This is also available online at the Antenatal Screening Wales website.

Weight and height checks in pregnancy

You will be weighed at your booking appointment, but you won't be weighed regularly during your pregnancy. Your height and weight are used to calculate your BMI (body mass index). Women who are overweight for their height are at increased risk of problems during pregnancy - you can find out more about being overweight when you get pregnant.

Most women gain 10-12.5kg (22-28lb) in pregnancy, most of it after they are 20 weeks pregnant. Much of the extra weight is due to the baby growing, but your body also stores fat for making breast milk after the birth. During your pregnancy, it's important to eat the right foods and take regular exercise.

Antenatal urine tests

You'll be asked to give a urine sample at all of your antenatal appointments. Your urine is tested for several things, including protein or albumin. If this is found in your urine, it may mean that you have an infection that needs to be treated. It may also be a sign of pre-eclampsia.

Pre-eclampsia affects 5% of pregnancies, and can lead to a variety of problems, including seizures (fits). If left untreated it can be life threatening. Pre-eclampsia can also affect the growth and health of the baby. Women with the condition usually feel perfectly well.

Blood pressure tests in pregnancy

Your blood pressure will be taken at every antenatal visit. A rise in blood pressure later in pregnancy could be a sign of pregnancy-induced hypertension. It's very common for your blood pressure to be lower in the middle of your pregnancy than at other times. This isn't a problem, but it may make you feel light-headed if you get up quickly. Talk to your midwife if you're concerned about it. Find out more about high blood pressure and pregnancy.

Blood tests in pregnancy

As part of your antenatal care you'll be offered several blood tests. Some are offered to all women, and some are offered only if you might be at risk of a particular infection or condition. All the tests are done to check that you and the baby are healthy.  You don't have to have them if you don't want to. Talk to your midwife or doctor, and allow yourself enough time to decide. They will also give you written information about the tests. Below is an outline of all the tests that can be offered.

The blood tests you may be offered include:-

Diabetes

You may be at higher risk of developing diabetes in pregnancy (gestational diabetes) if you are overweight, you've had diabetes in pregnancy before, you have a close relative with diabetes or you're of south east Asian, black Caribbean or Middle Eastern origin.

If you're considered to be high risk for gestational diabetes, you may be offered tests in pregnancy including blood tests.

Read more about gestational diabetes.

Anaemia

Anaemia makes you tired and less able to cope with loss of blood when you give birth. If tests show that you're anaemic, you'll probably be given iron and folic acid.

Antenatal Screening Wales

This page is about screening tests that are offered in pregnancy as part of the Antenatal Screening Wales programme. Further information for all these screening tests can be found  here  You can read the whole page, or click on the links to go directly to the information you want:

 Blood group and antibody screening in pregnancy

The people looking after you during your pregnancy need to know your blood group in case you ever need a blood transfusion. It is also important to know your Rhesus group.

What is your blood group?

Your blood group will be one of the following four main groups.

  • Group O
  • Group A
  • Group B
  • Group AB

You also have another blood group called the Rhesus group. You can be either Rhesus positive or Rhesus negative. For example, your overall blood group might be written as ‘group O Rhesus positive’.

What are red cell antibodies?

Antibodies are your body’s natural defence against anything that your body thinks is foreign.  Red cells carry oxygen in your blood. You may form antibodies if blood cells with a different blood group from your own enter your bloodstream. This can happen because of a blood transfusion or from your baby during pregnancy.

Red cell antibodies can pass from your bloodstream into your baby's. This can damage your baby's blood. Sometimes it causes a rare condition called haemolytic disease of the fetus and newborn (HDN). Symptoms of HDN include jaundice and anaemia (lack of red blood cells). Affected babies usually need to be admitted to hospital and treatment includes phototherapy (treatment with light) and sometimes blood transfusions.

If you are Rhesus negative

If you are Rhesus negative and your baby is Rhesus positive, then your body might produce antibodies to destroy these 'foreign' Rhesus positive blood cells. This sometimes happens during pregnancy, or more likely when your baby is delivered. If you are Rhesus positive, this problem does not usually happen.

Can haemolytic disease of the fetus and newborn (HDN) be prevented?

To help prevent HDN, if you are Rhesus negative you will be offered an injection or injections of anti-D immunoglobulin during pregnancy and after delivery if the baby is Rhesus positive. This can help stop your body making Rhesus antibodies and reduces the risk of problems in future pregnancies.

What is anti-D immunoglobulin?

Anti-D immunoglobulin (injection) is a blood product made from blood collected from donors.

Is anti-D immunoglobulin safe?

Occasionally anti-D immunoglobulin causes allergic reactions. How it is produced is very strictly controlled so the risk of a known virus being passed on to you from the donor is very low.

What are the advantages of having screening for my blood group and antibodies?

You will be offered a blood test early in your pregnancy.  If you have this test, you will know your blood group and whether you are Rhesus positive or Rhesus negative. It is less common to be Rhesus negative. About 15% (15 out of a hundred) of the population are Rhesus negative.

The test will also look for antibodies. It is important to know about these so if you ever need a blood transfusion this could be given safely. Rarely, antibodies present in your blood might carry the risk of affecting your baby as explained above. If this happens you and your baby can be given specialist care. This blood test is offered to you again around the 28th week of your pregnancy.

Screening for hepatitis B, syphilis and HIV in pregnancy

There are screening tests for all these infections and your midwife will offer you these.

You can choose whether or not you want the tests. The information in this leaflet will help you decide which tests you want to have. You can also talk about all the tests with your midwife before you decide, and ask about the local arrangements for the tests.

Why are the tests recommended?

Screening for hepatitis B, syphilis and HIV is offered and recommended in every pregnancy.  If you have one of these infections and it is not treated, your baby could catch the infection from you during the pregnancy, the birth or after the birth. 

All of these infections can be serious and if not treated may cause serious damage to your baby. Most people with these infections will not feel ill and will not know they have these infections. If you have one of these infections, treatment will significantly reduce the chance of your baby catching the infection.

How are the tests done?

The screening tests for hepatitis B, syphilis and HIV can all be carried out on one blood sample.  You can choose which tests are carried out.  Only a small amount of blood is needed.  The blood tests are usually done in early pregnancy. 

Why should Ihave the test?

By accepting screening for hepatitis B, syphilis and HIV you are deciding to find out if you have the infection so that everything possible can be done to protect your unborn child.

Where will the blood test be done?

Your midwife will tell you where you can have the test done.

What if I decide not to be screened for hepatitis B, syphilis or HIV?

If you decide not to be screened for hepatitis B, syphilis or HIV your midwife will ask you the reasons why to make sure you have understood the reasons for the test. Later on in your pregnancy, your midwife will ask you if you want to discuss the screening and will offer you the test again.

You can ask to be screened for hepatitis B, syphilis or HIV at any time in your pregnancy.

How will I get the results of my screening tests?

Your midwife will tell you how and when you will get the result of the tests you choose to have.

Will my results be confidential?

The NHS keeps the results of all blood tests confidential.  Hospital policies on how many people have access to your test results vary.  Your midwife will be able to explain the local arrangements to you.

More information

Information about these tests is included in this booklet and is on the Antenatal Screening Wales website at: www.antenatalscreening.wales.nhs.uk

If you need further information you can speak to:

•     your midwife, hospital doctor (your obstetrician) or GP, or

•     your nearest NHS sexual health clinic –  you can phone your local hospital and ask for the sexual health or GUM clinic.

Hepatitis B

What is hepatitis B?

Hepatitis B is a virus that infects the liver. Many people who have hepatitis B do not know they have it. Most adults with hepatitis B make a full recovery, but a small number become 'carriers' of the virus. People who are carriers may develop serious liver disease. 

If a pregnant woman has hepatitis B, her baby can be exposed to the hepatitis B virus during the delivery. A baby who catches the virus may have the infection for life and may be at risk of liver disease.

How can hepatitis B be caught?

Hepatitis B can be caught through:

  • a mother who is infected passing it to her baby during delivery
  • having unprotected sexual activity (without a condom) with someone who is infected
  • having contact with the body fluids of someone who is infected
  • having contact with unclean needles used in body piercing and tattooing
  • sharing infected needles and injecting equipment
  • a blood transfusion or blood products containing the virus (these are tested in the UK but not in all other countries), and
  • living for a long time in close contact with someone who is infected.

What are the advantages of having screening for hepatitis B in pregnancy?

Testing for hepatitis B is important because if doctors know about the infection before a baby is born, a course of vaccinations started soon after the birth can help stop the baby catching the virus. The vaccinations protect most babies from developing hepatitis B.

If you have hepatitis B, there is a very high chance that your baby will become infected (up to 70% or up to 70 out of a 100 times). If you have the screening test and are positive for hepatitis B, your baby can be vaccinated and the chance of your baby being infected will be less than 5% (that is, five times out of 100).

What are the disadvantages of not having screening for hepatitis B in pregnancy?

There is no good time to find out that you have hepatitis B. However, if you find out when you are pregnant, your baby can be vaccinated to help prevent them from catching the virus from you.

Should I have the screening test for hepatitis B? 

Only you can decide to have the test or not. All hospitals in Wales offer all pregnant women a screening test for hepatitis B because if you have hepatitis B the baby can be vaccinated to help stop them catching the virus from you.

What will the screening test result tell me?

A negative screening result tells you that you are very unlikely to have hepatitis B infection.

If you have caught hepatitis B in the few months before the blood sample is taken, the test will not be able to detect the infection.

It is important to remember that you can catch hepatitis B when you are pregnant. If you change your sexual partner during the pregnancy, you should use a condom.

If, while you are pregnant, you are worried that you might have caught HIV, hepatitis B, syphilis or other diseases which can be passed between people, you can ask your midwife to do another test at any time during your pregnancy.  You can also get confidential testing from your nearest sexual health clinic.

What is the diagnostic test for hepatitis B?

Sometimes the hepatitis B blood test can give an unclear (reactive) result and further tests may be needed to confirm you do not have an infection. 

If the screening test shows that you have hepatitis B, you will need another blood test to confirm the infection. 

What if I have hepatitis B?

If you have hepatitis B, your midwife or doctor will talk to you about how it will affect you and to plan the vaccinations the baby will need.

You may also be worried that other people in your family have the infection. They can also be tested and vaccinated if necessary.

Syphilis

What is syphilis?

Syphilis is a serious bacterial infection. Most people who have syphilis are unwell for only a short time at first and they may not be aware they have it. But if syphilis is not treated, it can cause serious problems later in life, including brain damage and heart problems.

How can syphilis be cought

Syphilis can be caught through:

  • a woman who has syphilis passing the infection to her unborn baby during pregnancy, or
  • having unprotected sexual activity (without a condom) with an infected person.

What are the advantages of having screening for syphilis in pregnancy?

Treatment with antibiotics in early pregnancy will help you and will usually prevent your baby from catching syphilis. Occasionally, babies may also need antibiotics when they are born. If you have syphilis when you are pregnant, it can lead to a miscarriage or can harm your baby.

What are the disadvantages of screening for syphilis in pregnancy?

There is no good time to find out that you have syphilis. However, if you find out when you are pregnant, you can have treatment to help prevent your baby from developing major problems.

Should I have the screening test for syphilis?

Only you can decide to have the test or not. All hospitals in Wales offer all pregnant women a screening test for syphilis because, if you have syphilis, treatment with antibiotics can help prevent your baby from developing major problems.

What will the screening test result tell me?

A negative screening result tells you that you are very unlikely to have syphilis infection.

If you have caught syphilis in the few weeks before the blood sample is taken, your body may not have started producing antibodies and the test will not be able to detect the infection.

It is important to remember that you can catch syphilis when you are pregnant. If you change your sexual partner during the pregnancy, you should use a condom.

If, while you are pregnant, you are worried that you might have caught HIV, hepatitis B, syphilis or other diseases which can be passed between people, you can ask your midwife to do another test at any time during your pregnancy.  You can also get confidential testing from your nearest sexual health clinic.

What are the diagnostic tests for syphilis?

Sometimes the syphilis blood test can give an unclear (reactive) result and further tests may be needed to confirm you do not have an infection. 

If the screening test is positive, you will be given an appointment with a doctor specialising in these types of diseases. This doctor will ask you questions, including questions about previous infections, to make a diagnosis and decide on the best treatment. 

The results of the screening test for syphilis are not always easy to understand. Sometimes the result of the screening test will come back positive because you have had syphilis in the past and have been treated, or you have a different and less serious problem.

What if I have syphilis?

If you have syphilis, your midwife or hospital doctor will talk to you about how it will affect you. You will probably be given antibiotics and need more blood tests.

Human immunodeficiency virus (HIV)

What is HIV?

HIV is a virus that attacks the immune system. It is the virus that can lead to acquired immune deficiency syndrome (AIDS). A person infected with HIV can look and feel well for many years. They may not know they are infected unless they have a blood test. However, this virus can be passed on to the baby during pregnancy, childbirth or by breastfeeding.

How can HIV be caught?

HIV can be caught through:

  • a mother who is infected passing it to her baby during pregnancy,  the delivery or breastfeeding
  • any unprotected sexual activity (without a condom) with someone who is infected
  • a blood transfusion or blood products containing the virus (these are tested in the UK but not in all other countries)
  • sharing infected needles and injecting equipment, and
  • contact with unclean needles used in body piercing and tattooing.

What are the advantages of having screening for HIV in pregnancy?

If you are HIV positive and do not know it, there is a high chance (25%, or 1 chance in 4) that your baby will become HIV positive.

If you are found to have HIV, a number of things can be done to lower the chance of you passing it to your baby. You will be offered specialist treatment and care. If you accept the treatment offered, the risk to your baby will be reduced to 1% or less (1 in 100 or less). The treatment may also help to keep you in better health.

What are the disadvantages of having screening for HIV in pregnancy?

There is no good time to find out that you are HIV positive. However, if you find out when you are pregnant, you can have treatment to help stop your baby catching the virus from you.

Should I have the screening test for HIV?

Only you can decide whether to have the test or not. All hospitals in Wales offer all women a screening test for HIV because if you are HIV positive it is possible to reduce the chance of the baby catching the virus.

What will the screening test result tell me?

A negative screening result tells you that you are very unlikely to have HIV infection. 

If you have caught HIV in the few weeks before the blood sample is taken, your body may not have started producing antibodies and the test will not be able to detect the infection.

It is important to remember that you can catch HIV when you are pregnant. If you change your sexual partner during the pregnancy, you should use a condom.

If, while you are pregnant, you are worried that you might have caught HIV, hepatitis B, syphilis or other diseases which can be passed between people, you can ask your midwife to do another test at any time during your pregnancy.  You can also get confidential testing from your nearest sexual health clinic.

What is the diagnostic test for HIV?

Sometimes the HIV blood test can give an unclear (reactive) result and further tests may be needed to confirm you do not have an infection. 

If the screening test shows that you are HIV positive, you will have another blood test to confirm the infection

What if I have HIV? 

If the test shows you have HIV, you will be able to plan with your midwife or hospital doctor what happens next. You will be offered specialist medical care and treatment to help with the infection. This will help reduce the risk of your baby getting the virus.

Treatment will include drug therapy. You may also be advised to have a Caesarean delivery and not to breastfeed. This treatment will not cure you but it will improve your health.

Does having the HIV screening test affect insurance policies? 

Insurance companies should not ask if someone applying for insurance has had a test for HIV. They can only ask whether someone has had a positive test result. If you already have a life insurance policy it will not be affected by taking a HIV test, even if the result is positive, as long as you did not withhold any important facts when you took the policy out.

Blood tests for infections in pregnancy

Be aware that you can still catch all these infections during pregnancy, after you've had a negative test result. This includes STIs (sexually transmitted infections) such as hepatitis B, syphilis and HIV, if you or your sexual partners take risks such as having unprotected sex. You can also get HIV and hepatitis if you inject drugs and share needles. Your midwife or doctor can discuss this with you.

HIV infection in pregnancy

If you think that you're at risk of getting HIV or you know that you're HIV positive, talk to your midwife or doctor about HIV testing and counselling. You can also get free confidential advice from the Sexual Health Line on 0800 567123 or you can talk confidentially to someone at Positively UK on 020 7713 0222.

Screening for sickle cell and thalassaemia in pregnancy

You can have a screening test during pregnancy to find out if you are a carrier of sickle cell or thalassaemia. If you are a carrier, the father of your baby will also be offered testing. There are a number of different types of carrier. If you and the father of your baby are both carriers of ‘important types’, your baby could inherit a sickle cell disorder or thalassaemia major.

You can choose whether or not to have these tests.

What are sickle cell disorders and beta thalassaemia major?

Sickle cell disorders and thalassaemia major are serious inherited blood conditions. They affect the haemoglobin in the red blood cells. Haemoglobin is important because it carries oxygen around the body. People who have these conditions will need specialist care throughout their lives. There are also other, less common haemoglobin disorders.

Many of these are not as serious.

Sickle cell disorders

People with a sickle cell disorder can:

  • have tissue and organ damage and varying degrees of symptoms
  • have attacks of severe pain where they need to stay in hospital, and
  • be more prone to serious infections.

Beta thalassaemia major

People with beta thalassaemia major have:

  • severe anaemia and need blood transfusions every four to six weeks as well as other treatments.

How are the disorders inherited?

Sickle cell and thalassaemia are genetic disorders. They are passed on in families.

If both parents carry a sickle cell or thalassaemia gene, the baby may have a one in four, or 25% chance of having a sickle cell disorder or beta thalassaemia major.

If only one parent (either the mother or father) has the sickle cell or thalassaemia gene, it is very unlikely that their baby will have a sickle cell disorder or beta thalassaemia major. But the baby may be a carrier. That means that, like the mother or father, the baby will have the sickle cell or thalassaemia gene, but the gene does not usually cause problems.

Who can be affected?

Anyone can be a carrier of sickle cell or thalassaemia.

The chances of being a carrier of sickle cell or thalassaemia are higher for certain groups of people. This means you are more likely to be a carrier if your family, no matter how many generations back, come from the Mediterranean, Africa, the Caribbean, the Middle East, South Asia, South America or South East Asia.

The test

The test is a blood test which can be done with other blood tests, usually early in pregnancy.

The test is only offered to women with a higher chance of carrying sickle cell or thalassaemia. See ‘Who is offered the test?’ to see if you are in this group.

As part of your antenatal care, you will be offered a routine blood test (a full blood count) to check your haemoglobin level to see if you are anaemic. The full blood count can also find some types of thalassaemia.

The midwife will ask you if you would like to have thalassaemia screening as part of the full blood count test. If your full blood count test suggests that you might carry thalassaemia, the laboratory may also screen your blood for sickle cell disorders and thalassaemia.

Who is offered the test?

You should be offered the test if:

  • you or the biological father of the baby has a family history of sickle cell or thalassaemia
  • you, the biological father of the baby, anyone in your family, or anyone in the biological father of the baby’s family, no matter how many generations back, came from anywhere in the world apart from the UK and the Republic of Ireland
  • you or the biological father of the baby does not know your family history – for example, you or the biological father of the baby were adopted, or
  • you have unexplained anaemia.

What are the advantages of having screening for sickle cell and thalassaemia in pregnancy?

If you are a carrier of sickle cell or thalassaemia, it is important to know so you can have the right kind of care during your pregnancy.

Women who know their baby has a high chance of inheriting a sickle cell disorder or thalassaemia major can have a diagnostic test to find out if the baby is affected.  This could be done by either chorionic villus sampling (CVS) or amniocentesis. If the baby is affected, the woman can decide whether to continue with the pregnancy or to end it.

What are the disadvantages of having screening for sickle cell and thalassaemia in pregnancy?

Having the test may make you anxious if you find out you carry sickle cell or thalassaemia. Some women would be offered a diagnostic test to see if the baby is affected. Because the diagnostic tests can cause a miscarriage, many women find this a difficult decision. Some women may wish they had not had the screening test because making this decision is difficult. 

Should I have the blood test for sickle cell and thalassaemia?

Only you can decide to have the test or not. Some women want to find out if their baby has sickle cell or thalassaemia, and some do not. Having the test may cause anxiety as the result may mean that you are offered further tests.

Where will the blood test be done?

Your midwife will tell you where you can have the test done.

Results

Will my results be confidential?

The NHS keeps the results of all tests confidential.  Hospital policies vary on how many people in the NHS have access to your test results.  Your midwife will be able to explain the local arrangements to you.

How will I get the result from my screening test?

Your midwife will tell you how and when you will get the result of the test.

What will the results tell me?

If the result shows you are not a carrier, it is very unlikely your baby could have a sickle cell disorder or thalassaemia major. Although the test is very accurate, a small number of results may be unclear. If this happens, you will be offered another test.

If the test shows you are a carrier or a possible carrier, you will be able to talk to a specialist midwife or genetic specialist and they will give you more information. They may suggest you ask the biological father of the baby to have a blood test to find out if he is a carrier. If his test result shows he is not a carrier, it is very unlikely your baby will have a sickle cell disorder or thalassaemia major.

What if the biological father is also a carrier?

If the test shows the father of your baby is a carrier, there may be a one in four (or 25%) chance your baby could have a sickle cell disorder or beta thalassaemia major. You can then decide whether to have more tests to find out if your baby is affected. These tests are called diagnostic tests. If you choose not to have more tests, your baby can be tested at birth for sickle cell disorders or for beta thalassaemia major. This means that if  the baby is affected, treatment can start early.

What are the diagnostic tests?

Chorionic villus sampling (CVS) and amniocentesis

CVS and amniocentesis are diagnostic tests. They are accurate ways of testing for sickle cell disorders and thalassaemia major. If you decide to have a diagnostic test, you and the father of the baby will be asked to give another blood sample to help the laboratory give an accurate diagnosis.

What is CVS?

CVS is a procedure during which a doctor removes a small amount of tissue from your placenta (afterbirth) during the pregnancy. The cells in this tissue are tested in the laboratory to look at your baby's chromosomes. You can usually have CVS after you are 11 weeks pregnant.

CVS involves some risk.  It can cause a miscarriage in 1% to 2% of pregnancies (one in every 50 to 100 pregnancies).

What is an amniocentesis?

An amniocentesis is a procedure to remove 15 to 20 millilitres (about three to four teaspoons) of amniotic fluid from around the baby in the womb.  The cells from your baby that are floating in this fluid can be tested in the laboratory.

 It can be done after you are 15 weeks pregnant.

Amniocentesis involves some risk. It causes a miscarriage in around 1% of pregnancies (one in every 100 pregnancies). 

What are the possible results from diagnostic tests?

If you have CVS or amniocentesis, the result may show:

  • that your baby does not have this problem, or
  • your baby has a sickle cell disorder or thalassaemia major. You can then decide whether to prepare for the birth of a baby with sickle cell or thalassaemia major or to end your pregnancy.

CVS and amniocentesis can detect other chromosome abnormalities and you can get more information in the CVS and amniocentesis leaflet.

More information

You can get information about sickle cell and thalassaemia from your midwife or your hospital doctor (your obstetrician) and from www.antenatalscreening.wales.nhs.uk

Other organisations

Sickle Cell Society

Website: www.sicklecellsociety.org

UK Thalassaemia Society

Website: www.ukts.org

 

 


Last Updated: 08/11/2017 13:27:07