Screening tests for you and your baby
Antenatal and Newborn Screening
What are screening tests?
Screening tests are used to find people at higher chance of a health problem. This means they can get earlier, potentially more effective treatment, or make informed decisions about their health. It can be helpful to imagine screening like putting people through a sieve. Most people pass straight through but a small number get caught in the sieve. The people caught in the sieve are those considered to have a higher chance of having the health problem being screened for.
What is the difference between screening tests and diagnostic tests?
A screening test can find out if you, or your baby, have a high or low chance of having a health problem. But it cannot usually tell you for certain, so people found to have a high chance of a problem will often be offered a second test. This is called a diagnostic test and gives a more definite ‘yes’ or ‘no’ answer.
It is important to understand the purpose of all screening so that you can make an informed decision about whether to have them. You will be given a ‘Screening tests for you and your baby’ booklet which gives detailed information on each screening test available during and after pregnancy for you and your baby.
Please click on the graphic above to access the booklet
Booklet also available in the following languages –
- Chinese Simplified
It is useful to know your blood group in case you need to be given blood, for example if you have heavy bleeding (haemorrhage) during pregnancy or birth. The test tells you whether you are blood group rhesus negative or rhesus positive. Women who are rhesus negative may need extra care to reduce the risk of rhesus disease.
People who are rhesus positive have a substance known as D antigen on the surface of their red blood cells. Rhesus negative people do not. A rhesus negative woman can carry a baby who is rhesus positive if the baby's father is rhesus positive. If a small amount of the baby's blood enters the mother's bloodstream during pregnancy or birth, the mother can produce antibodies against the rhesus positive cells (known as anti-D antibodies).
This usually doesn't affect the current pregnancy, but if the woman has another pregnancy with a rhesus positive baby, her immune response will be greater and she may produce a lot more antibodies. These antibodies can cross the placenta and destroy the baby's blood cells, leading to a condition called rhesus disease, or haemolytic disease of the newborn. This can lead to anaemia and jaundice in the baby.
Anti-D injections can prevent rhesus negative women from producing antibodies against the baby. Rhesus negative mothers who haven't developed antibodies are therefore offered anti-D injections at 28 weeks of pregnancy, as well as after the birth of their baby. This is safe for both the mother and the baby.
Hepatitis B, HIV (human immunodeficiency virus) and Syphilis Screening
About these conditions
Hepatitis B and HIV are passed on in blood and body fluids through sexual contact or infected needles. These viruses can also be passed from mother to baby.
Hepatitis B virus affects the liver and can cause acute (immediate) and chronic (long-term) ill health. Specialist care is needed for pregnant women with hepatitis B.
Vaccination of the baby in the first year of life greatly reduces the risk of the baby developing hepatitis B.
HIV weakens the immune system making it difficult to fight off infections. It can eventually lead to AIDS (acquired immune deficiency syndrome). If untreated, it can be passed from mother to baby in pregnancy, when giving birth or by breastfeeding. Treatment in pregnancy greatly reduces the risk of passing on HIV to the baby from 1 in 4 (25%) to less than 1 in 200 (0.5%).
Syphilis is an infection passed on through sexual contact. It can be passed from mother to baby during pregnancy. If it is untreated, it can result in serious health problems for the baby or cause miscarriage or stillbirth.
What does the test involve?
A blood sample is taken from your arm.
Sickle cell disease (SCD) and Thalassaemia Screening
Sickle cell disease (SCD) and thalassaemia major are inherited blood diseases. They affect haemoglobin, a part of the blood that carries oxygen around the body. People who have these conditions will need specialist care throughout their lives.
People with SCD can have attacks of very severe pain, get serious, life-threatening infections and are usually anaemic (their bodies have difficulty carrying oxygen). Babies with SCD can receive early treatment, including immunisations and antibiotics, which, along with support from their parents, will help prevent serious illness and allow them to live a healthier life.
People with thalassaemia major are very anaemic and need a blood transfusion every 3 to 5 weeks, and injections and medicines throughout their lives.
There are also other, less common, less serious haemoglobin diseases that may be found.
It is recommended to have the test before you are 10 weeks pregnant or as soon as care is accessed. SCD and thalassaemia are inherited diseases that are passed on from parents to children through unusual haemoglobin genes. Genes are the codes in our bodies for things such as eye colour and blood group. Genes work in pairs. For everything that we inherit we get one gene from our mother and one from our father.
People only have SCD or thalassaemia if they inherit 2 unusual haemoglobin genes – one from their mother and one from their father. People who inherit just one unusual gene are known as “carriers” (some people call this having a “trait”). Carriers are healthy and do not have the disease, although they can experience some problems in situations where their bodies might not get enough oxygen, for example, having an anaesthetic.
When both parents are carriers the baby has:
- 1 in 4 (25%) chance of not being affected – the baby will not have or carry a disease
- 1 in 4 (25%) chance of inheriting both unusual haemoglobin genes and having a haemoglobin disease
- 2 in 4 (50%) chance of inheriting 1 unusual haemoglobin gene and being a carrier
What does the test involve?
A blood sample is taken from your arm.
1st Trimester Scan (12-14 weeks)
All women are offered ultrasound examinations (scans) during their pregnancy to provide an estimated date of delivery, to see if they are having more than one baby and also to detect any problems.
This first routine scan is carried out for the following reasons:
- To confirm when the baby is due:
The early scan helps us to work out the date when your baby is due. We might suggest a different date from that indicated by your last period. This is because not all pregnancies are conceived exactly 14 days after the first day of the last period. If your pregnancy is the result of assisted conception, we would normally calculate the delivery date from the date of your treatment. It is important to know your final due date for your care later in pregnancy.
- To see if you are expecting more than one baby:
most families would like to know if twins are expected to help them to plan ahead. It is also important to help us to plan your care appropriately.
- To confirm the baby’s heart is beating
- To detect problems of development that can sometimes be seen at this early stage
- To detect other problems such as ovarian cysts (in you, not your baby)
- To perform Combined screening for Down’s syndrome (also known as Trisomy 21 or T21), Edwards’ syndrome (Trisomy 18/T18) or Patau’s syndrome (Trisomy 13/T13) if you choose to have the screening.
The optimum time for the nuchal translucency scan to be performed is around 12 weeks but it can only be performed between 11 weeks and 2 days and 14 weeks and 1 day.
As with all tests in pregnancy, combined screening for Down’s syndrome is optional. It is not diagnostic. This means that the screening will only identify a baby as being at a ‘Increased Chance’ or ‘Low Chance’ of being affected with one of the three conditions. The screening will not definitely determine whether a baby does or does not have one of the conditions. Women who are identified as ‘High Chance’ will be contacted directly and offered further testing.
If you do not wish to have combined screening for Down’s syndrome, Edward’s syndrome or Patau’s syndrome, you will be offered a dating scan. We also like to arrange this for around 12 weeks, but it can be performed between 10 and 14 weeks.
Sometimes, it is not possible to take measurements of the nuchal translucency. In this case, you will be offered the quadruple test (a blood test which can be performed between 14 weeks and 20 weeks) as your screening test.
Occasionally during the scan, a miscarriage might be diagnosed even though you might still 'feel pregnant'. In this case, the sonographer (the person who does the scan) will discuss the scan findings with you and arrange for a doctor to see you in our Early Pregnancy Unit.
2nd Trimester Scan
All women are offered a detailed or 'anomaly' scan between 18 weeks and 0 days and 20 weeks and 6 days. It's called the anomaly scan because it checks for structural abnormalities (anomalies) in the baby.
We screen for 11 specific conditions in accordance with the fetal anomaly screening programme:
- Spina bifida
- Cleft lip
- Diaphragmatic hernia
- Seven serious cardiac abnormalities
- Bilateral renal agenesis
- Lethal skeletal dysplasia
- Edwards' syndrome (Trisomy 18)
- Patau's syndrome (Trisomy 13)
The scan will also check the position of the placenta.
Ultrasound findings which are not normal
For the majority of women, the 18-20 week scan is a reassuring and memorable experience, but sometimes problems are found. If any abnormalities are detected during the scan the sonographer will discuss these with you and arrange for you to see a Screening Midwife who will discuss the scan findings with you in more detail and will arrange additional scans and reviews to gain further information for you.
Some findings may not be significant and will resolve themselves. Others can forewarn of problems that would otherwise not be detected until birth or even infancy. Some information can cause considerable anxiety and can lead parents to consider options regarding continuation of the pregnancy.
It must be remembered that a normal scan does not guarantee fetal health and well-being.
It is important to remember that only some abnormalities can be detected by scan; others are difficult to detect and therefore may be overlooked by scan, while some do not develop until later in the pregnancy or after birth.
Fetal gender – If you wish to know the gender of your baby, this can be done during the 20 week Anomaly scan only. Fetal sexing by ultrasound is not 100% accurate. This will only e verbally communicated to the woman at the time of the scan. Any requests for the fetal gender to be written down will be declined. The Sonographer may not always be able to see the gender of your baby for a number of reasons. Rescans are not offered for fetal sexing.
Your partner is welcome to join you in the scan room, but as the scan is an important clinical investigation which requires maximum concentration, we would suggest that you please make arrangements for childcare. We would also appreciate it if you/your partner do not bring food and/or drink into the scan room.
It is essential that our sonographers are allowed to concentrate fully without the distraction of filming. Therefore the use of mobile phone cameras, videos and other photographic equipment is not allowed during your ultrasound scan.
Postnatal Screening for Baby
Newborn Infant Physical Examination (NIPE)
Within 72 hours of giving birth, you will be offered an all over physical examination for your baby. This will include 4 specific screening tests to find out whether your baby has a problem with their eyes, heart, hips or, in boys, their testes and would benefit from early investigation and possible treatment.
The screening tests are carried out again between 6 and 8 weeks of age as some conditions do not develop or appear until then.
Eyes – the examination checks the appearance and movement of the eyes and investigates whether your baby has cataracts and other problems. About 2 or 3 in 10,000 babies are born with cataracts, a clouding of the transparent lens inside the eye. The examination cannot tell how well your baby can see.
Heart – there is a general examination of your baby’s heart and sometimes murmurs are picked up. A murmur is a noise made by the blood as it passes through the heart. In almost all cases when a murmur is heard, the heart is normal. Murmurs are common in babies and this does not always mean there is a problem. However, around 1 in 200 babies have a heart problem that needs treatment.
Hips – babies can be born with hip joints that are not formed properly and if untreated this can lead to a limp and to joint problems. About 1 or 2 in 1,000 babies have hip problems that need treatment.
Testes – baby boys are checked to make sure their testes are in the right place. It can take several months for testes to drop down (descend) into the scrotum. About 1 in 100 baby boys have problems with undescended testes that need treatment to reduce the risk of problems later in life, such as reduced fertility.
To find babies who have a hearing loss so that support and advice can be offered right from the start.
One to 2 babies in every 1,000 are born with a permanent hearing loss in one or both ears. Most of these babies are born into families with no history of hearing loss.
Permanent hearing loss can significantly affect a baby’s development.
Finding out early can give these babies a better chance of developing speech and language skills. It will help babies make the most of relationships with their family and carers from an early age.
Newborn Bloodspot Screening
To find out if your baby has any of 9 rare but serious health conditions. Early treatment can improve your baby’s health and prevent severe disability or even death. If you, the baby’s father, or a family member already has one of these conditions, please tell your health professional straight away.
- Sickle Cell Disease
- Cystic Fibrosis
- Congenital Hypothyroidism
- Phenylketonuria (PKU)
- Medium-chain acyl-CoA dehydrogenase deficiency (MCADD)
- Maple syrup urine disease (MSUD)
- Isovaleric acidaemia (IVA)
- Glutaric aciduria type 1 (GA1)
- Homocystinuria (pyridoxine unresponsive) (HCU)
Does my baby need to have this test?
Screening your baby for all these conditions is recommended because it could save your baby’s life but it is not compulsory. You can choose to have screening for SCD, CF or CHT individually but can only choose to have screening for all 6 IMDs or none at all. If you do not want your baby screened for any of the conditions, please talk to your midwife.
Can my baby have the test later if I change my mind?
Yes. Babies can be screened up to 12 months of age for all the conditions except CF (only up to 8 weeks of age). If you have any concerns about the tests, please discuss them with your health professional.
Most babies will have normal results indicating that it is unlikely that they have any of the conditions. A small number of babies will screen positive for 1 of the conditions. This does not mean they have the condition but they are more likely to have it. They will be referred to a specialist for further tests.
Screening for cystic fibrosis finds some babies who may be genetic carriers of the condition. These babies may need further testing. Screening does not detect all carriers.
Occasionally, other medical conditions might be identified through these screening tests. For example, babies with beta thalassaemia major (a serious blood disease) will usually be detected. These children also need to be referred for lifelong treatment and care.
If you have any further questions or queries regarding screening tests for you and your baby, please do not hesitate to contact the Screening Team at Mid Essex at - Antenataland.email@example.com please email your details and any questions you may have and we will endeavour to reply to your email within five working days.
Monday to Friday 9-5pm
Emma Neate – Screening Coordinator
Sarah Iskander – Screening Midwife
Karen Thompson – Failsafe Officer