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The Rotunda was the first maternity hospital in dublin to get the national baby friendly hospital award

Ultrasound & Fetal Medicine

We provide diagnostic scans, blood and other screening tests to out rule possible abnormalities with your baby. The staff working in this area are highly specialised and will provide you with all the support and advice you may require.

Ultrasound Scans in Pregnancy

Woman getting ultrasound

Women are offered an ultrasound scan at their booking visit. This scan is able to check your dates, the number of babies you are expecting and it will show you the baby’s heart beating. You will need to have a full bladder for any scan before 15 weeks.

Special gel is applied to your tummy and a probe is moved up and down your tummy. Ultrasound uses sound waves to build up a picture of your baby. An image of your baby, the placenta (afterbirth) and the fluid surrounding your baby appears on the screen. The staff member will measure your baby so that we know when your baby is due to be born. This is very important, especially if you don’t know the date of your last period or if you had irregular periods or you have recently come off the pill.

Your partner may accompany you to all your scan appointments but unfortunately children are not allowed. Recording devices are not allowed.

You can usually get a printout picture of your baby at the end of the examination. To keep your picture in good condition, don’t leave it in sunlight for a long period of time and don’t laminate it, as this will cause the picture to fade, losing your precious memories.

Fetal anatomy scan

All women attending the Rotunda Hospital are offered a detailed ultrasound scan at about 20 weeks to see if their baby is developing normally. This is known as the fetal anatomy scan. A large amount of detail about your baby will be visible at this scan. Seeing your baby on the ultrasound screen is a very exciting and emotional time.

What can this scan detect?

This ultrasound scan is very accurate but it cannot diagnose all birth defects. Sometimes, we cannot get clear images of the baby due to the way that your baby may be lying in the womb or because of the mother’s size. If the scan is complete, we would expect to pick up at least:
  •  95% of spina bifida
  •  80% of cleft lip
  •  30-50% of major congenital heart defects

This scan can also identify 50% of babies with Down syndrome, but the first trimester screening (FTS) test and non-invasive prenatal test (NIPT) are better for this. Because 30-50% of babies with Down syndrome appear normal on ultrasound, only a chorionic villus sampling procedure or amniocentesis can give you this information for certain. It is also important to realise that ultrasound scans in pregnancy do not detect problems like cerebral palsy or autism.

Some babies with chromosomal abnormalities have signs called ‘soft’ markers. Some such markers increase the risk for a chromosomal abnormality while others are not significant if identified on their own.

While some babies with chromosomal abnormalities have these soft markers, it is important to remember that 15% of normal babies have at least one ultrasound soft marker. The only way to diagnose or exclude a chromosomal problem for certain is to have an amniocentesis. If you would prefer not to know about these markers please inform us prior to the scan.

If the scan suggests a problem or an abnormality, you and your partner will be informed. We will arrange for you to meet with a consultant who specialises in fetal medicine as soon as possible or within 2 working days.

A full support service will be available for you should any problems be detected, including referral to appropriate specialists. It is important to remember that you will be involved in all decisions regarding the management of your pregnancy. A copy of your report will be sent to your referring hospital, doctor or midwife to ensure good communication.

Why have a fetal anatomy scan?

The vast majority of babies are normal. However all women, whatever their age, have a small chance of delivering a baby with a physical or mental disorder. Many such abnormalities can be diagnosed or ruled out with the fetal anatomy scan.

Reasons to have this scan include:

  • to reassure you that your baby is likely to be structurally normal;
  • to confirm your dates;
  • to detect birth defects, such as spina bifida or heart problems; 
  • if you are concerned about the chances of chromosome problems like Down syndrome, subtle markers can be sought that may suggest a higher risk that your baby may have one of these problems;
  • if you want to know the sex of your baby, this can usually be seen at this scan.
When you attend for this scan we will tell you about everything that we see, unless you advise us that there are certain things that you don’t want to know about, such as the sex of your baby or markers for chromosome problems. Should you have any questions or concerns please contact the staff in the prenatal diagnosis clinic by phoning 01 817 6572.

Scans in late pregnancy

The anatomy scan is usually the last scan taken during pregnancy unless you are referred by the medical team for further scans.  Ultrasound scans can also be used in late pregnancy to determine if the baby is growing properly and to check the liquor or fluid around your baby. They help to compile a ‘biophysical profile’ of your baby. This profile is a list of things that are checked and given scores by the midwife or doctor to see how well your baby is doing. The things checked and scored include the baby’s heart rate, the baby’s muscle tone, breathing movements and the amount of fluid around the baby. Other reasons for ultrasound scans in late pregnancy are if there is a possibility your waters have broken or to locate the exact position of the placenta. However, towards the end of pregnancy it can be difficult to get a complete picture on the printout, as the baby is now too big.

Fetal Medicine

Fetal medicine focuses on the management of high risk pregnancies and includes the assessment of fetal (unborn baby) growth and the diagnosis of fetal illness and abnormality. Fetal medicine can be broadly divided into two branches: prenatal diagnosis and fetal treatment. Prenatal diagnosis is the ability to detect abnormal conditions of the fetus. The most common test used for prenatal diagnosis is ultrasound. Some abnormalities may be identified from additional blood screening or invasive diagnostic tests. Fetal treatment includes a series of interventions performed on the fetus with the aim of achieving fetal wellbeing. These interventions include medical (non-invasive) and surgical procedures.

Contact details:
Phone: 01 – 817 6572

Referral form

Please complete the form if you wish to refer a woman to the unit for review or treatment.

Fetal Medicine Referral Form.docx

Prenatal diagnosis clinic

The prenatal diagnosis clinic (PNDC) provides pregnancy screening, diagnostic testing, intrauterine therapies, and patient support and counselling. We provide a standard of excellence in the field of prenatal diagnosis and fetal medicine for patients from our own catchment area as well as for women referred to the clinic from other centres around the country. Our ultrasound scans are performed to the highest international standards and women are supported by informative and sensitive counselling services. Women and their partners receive personalised care by a team of specialist doctors and midwives.

Antenatal care staff

Services provided include:

Screening for fetal chromosomal defects

First trimester screening (FTS) is the most accurate way of estimating the chances of your baby having a chromosomal problem and is carried out between 11 - 13 weeks gestation. This test measure the level of three proteins normally found in the blood during pregnancy. Along with a special ultrasound scan, this helps us to calculate the risk of your baby having a chromosomal abnormality.

The non-invasive prenatal test (NIPT) is a new screening test that helps us to identify if your baby is likely to have a chromosomal condition, for example, Down syndrome, (Trisomy 21), Edward syndrome (Trisomy 18) or Patau syndrome (Trisomy 13).  The blood test can be performed from 10 weeks of pregnancy onwards.

These tests are not carried out routinely on all pregnant women. It is an ‘opt-in’ service. Costs may apply for these screening tests. Please contact the department for further information.

Please follow these links for information on the screening tests:
First trimester screening
Non-invasive prenatal test

Diagnosis of chromosomal and genetic conditions

Chorionic villus sampling (CVS) is a test where a small sample of tissue is taken from your baby’s placenta, which is tested for chromosomal or genetic abnormalities. The test is performed between 10 weeks + 5 days and 14 weeks gestation. Amniocentesis involves taking a small amount of amniotic fluid from the pregnancy sac around the baby in the womb, which is tested for chromosomal or genetic abnormalities. This test is performed after 16 weeks of pregnancy.

Please follow these links for information on these diagnostic tests:
Chorionic villus sampling

Fetal cardiology

If you have a family history of certain heart conditions or if your baby is suspected of having a heart problem on ultrasound scan you will need to attend the clinic for a fetal cardiac echo (scan) with a fetal medicine consultant. You may be referred to a special cardiac clinic in the Coombe hospital where you will meet a paediatric cardiologist. If there is an abnormality they will support and counsel you and will discuss the plan of care which is best for you and your baby.

Monitoring fetal growth and wellbeing

Sometimes babies do not grow at the appropriate rate for their gestation. If this happens we will need to investigate the cause and monitor your baby more frequently with ultrasound scans during the remainder of your pregnancy.

Complicated multiple pregnancies

If you have a twin or triplet pregnancy you will attend a special clinic to monitor your babies’ growth and wellbeing. Sometimes babies share amniotic fluid sacs and placentas, which makes the pregnancy more complicated. However there are some treatments available if complications develop, including laser ablation.

Intrauterine therapies

Some babies require treatment while they are still in the womb. These may include intrauterine transfusion, laser ablation, vesicocentesis and cordocentesis. We will provide you with information on any treatments you may require.


We will need to know your blood group if you are having any invasive procedure. Therefore, if you are not attending the Rotunda for antenatal care please bring details of your blood group with you. If you are on any medications, please contact us a couple of days before your appointment as you may need to stop or reduce your medication before the procedure.

prenatal diagnosis unit scan

How we will support you if there is an abnormality or problem identified with your baby

While most women give birth to healthy babies, about 3% will have a major birth defect. Most of these result from either a genetic or chromosomal disorder. When this happens we will provide parents with expert personal counselling and support and detailed information so that they can be involved in making decisions about their care. We will support you no matter what decisions you make about your pregnancy.

All the doctors and midwife specialists who work in the fetal medicine centre have had special training in diagnosing abnormalities and in supporting couples who are attending the clinic. They work very closely with the paediatric team, specialist consultants in the paediatric hospitals and with the bereavement support team, where appropriate. Weekly multidisciplinary team meetings are held to discuss patients and assist with planning the management and care for the pregnancy and birth. We will provide you with the contact details and information on the relevant support groups and organisations.

Please see the following websites for information on some genetic or chromosomal conditions:

National Centre for Medical Genetics
Down’s Syndrome
Support Organisation for Trisomy 13/18 (SOFT)

If we know that a baby may be stillborn or may not live for long after birth, parents may also wish to contact a bereavement support organisation when the diagnosis has been made. They provide helpful and important information to help and support parents at the time they are told the sad news that their baby has died or is expected to die shortly after birth.

Please see the following websites for information on these bereavement support groups and to view their information booklets.

A Little Lifetime

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