OBSTETRIC ULTRASOUND SCAN

PREGNANCY (Obstetric) ULTRASOUND What is pregnancy (obstetric) ultrasound imaging? What are the common uses of the procedure? How should I prepare for the scan? What types of scan are available? What will I experience during the examination? How do I get the results? Frequently asked questions

What is pregnancy (obstetric) Ultrasound imaging? Pregnancy ultrasound is a method of obtaining images of your baby, inside the uterus, by using high frequency sound waves. No x-rays or ionising radiation is involved and there are no reported side effects for this procedure at the diagnostic power levels that our machines use.

What are the common uses of the procedure? Pregnancy ultrasound imaging is widely used to evaluate the baby. It can determine if a baby is present, the position of your baby and how many there are. It will also help the diagnosis of abnormalities or problems, help determine the age of the pregnancy and your due date as well as evaluating the position of the placenta in relation to the birth canal.

How should I prepare for the scan? You need to have a full bladder only in very early pregnancy. In later pregnancy, it can be useful to have some fluid in your bladder so the birth canal can be seen.

What types of scan are available? Early viability scan (6 – 10 weeks) This scan can confirm the number of babies in the uterus (womb) and can detect a heartbeat by 6 weeks. In early pregnancy, it may be necessary to perform an internal scan (trans-vaginal scan) to obtain clearer images of your baby and its surroundings. A clear explanation of the procedure and what has been found during the scan will be given to you during the examination. Scans at this stage in pregnancy are reassuring for women experiencing bleeding, pain or who have had previous miscarriages. Nuchal translucency scan (11– 13+6 weeks) for Down's syndrome and other chromosomal abnormalities with a blood test Most of the babies we scan with ultrasound at the clinic are normal and go on to develop normally in the womb. However all women, whatever their age, will have a small risk of having a baby with a problem. One of these problems can be due to a chromosomal abnormality such as Down’s syndrome. The most accurate way of estimating the risk of a baby having a chromosomal abnormality without having an invasive test such as an amniocentesis or chorionic villus sampling (see below) is to undertake a nuchal translucency scan with a blood test. This combined test has an accuracy of about 92% whilst the nuchal scan on its own has an accuracy of about 70%. The nuchal translucency is an area of fluid behind the baby’s neck. An increase in the amount of fluid may indicate an increased risk of a chromosomal abnormality, such as Down’s syndrome. We can now combine the mother’s age, the size of the baby, the nuchal thickness measurement, the presence or absence of a nasal bone with a blood sample taken from the mother to give a more accurate risk assessment of a chromosomal abnormality as early as 12 weeks. We usually take the blood sample from 10 weeks onwards and send it away to a laboratory specialising in this type of screening. When we take your blood we will carry out an ultrasound scan to: Confirm your dates - this is particularly relevant if you cannot recall the date of your last period or have an irregular cycle. We will be able to tell you when your baby is due Show you the baby’s heartbeat - this is particularly reassuring at this stage in pregnancy when you cannot feel your baby move or if you have had a miscarriage in the past Detect multiple pregnancies - approximately 2% of natural conceptions and 10% of assisted conceptions result in multiple pregnancies. We can show you that your babies are developing normally and see if they are identical or not Diagnose an early pregnancy failure – sadly about 3% of women who come for a nuchal scan may find that the baby has died, often several weeks before and without any warning We then ask you to come back after 12 weeks so we can measure the nuchal thickness and check your baby’s anatomy as some problems or abnormalities may be visible at this gestation but this still means that you should attend for your 20 week scan (you can choose to do this at KMI or in your local NHS hospital) as not all problems can be detected at this stage. If you cannot come in two visits it generally is not a problem - we will discuss the different options we can offer you. A computer program will be used to estimate the risk by combining all the factors. Most of the examinations are low risk. However, if you are one of the unfortunate few with a high risk, the results will be discussed with you and the follow up counselling will be arranged. This does not have to be on a private basis. We have been fully trained by the Fetal Medicine Foundation and are regularly audited by them to ensure we continue to perform at the highest standard. [www.fetalmedicine.com]. As we have mentioned the only way to know for sure whether or not the baby has a chromosomal abnormality is by having an invasive test such as chorion villus sampling (CVS) or amniocentesis. We can arrange for you to have these done privately through the Fetal Medicine Centre or refer you to a consultant in the NHS Chorionic villus sampling (CVS) is offered up to 15 weeks of pregnancy. A very fine needle is inserted through the maternal abdominal wall, usually under ultrasound control, into the placenta and a tiny piece of placenta is removed. This is sent to a specialised laboratory where it is used to examine the developing fetal chromosomes. Results are usually available within a week Amniocentesis is another test offered from 15 weeks of pregnancy. A very fine needle is passed through the mother's abdominal wall into the fluid which surrounds the baby (amniotic fluid). This is usually carried out under ultrasound control. A small amount of fluid is aspirated and sent to the laboratory to examine the fetal chromosomes. The results are usually available within two weeks Both these tests can carry a risk of miscarriage of about 1% but this risk is dependant on the clinician carrying out the test. Fetal anomaly scan (20 – 23 weeks) After checking your baby’s heartbeat, the main purpose of this scan is to check your baby’s anatomy for normality. A thorough examination of your baby’s brain, heart, spine, kidneys, organs and limbs will be undertaken. The placenta will be checked for its position and measurements of your baby will be performed to ensure it is growing normally. Anomaly scans are important as they can reassure the parents that everything appears to be as it should be; however, in a few cases a potential problem may be indicated. In these cases a further follow up scan may be needed and it may be necessary for us to discuss the problem with your midwife or doctor. We will explain any complications of the pregnancy with you at the time of scan and give you advice and guidance where we can. We are happy to look for the sex of your baby during this scan, however, ultrasound is not 100% accurate and this is only an opinion and not a guarantee of one particular gender. Growth and fetal well-being scan (24 weeks - to term) Measurements of your baby’s head, abdomen and femur (thigh) are taken and plotted on graphs to check that your baby is growing normally. From these measurements we are able to estimate your baby’s weight. The amniotic fluid (water surrounding the baby) is assessed along with the position of the placenta to ensure that it is not near the birth canal which could affect delivery. This scan can also confirm the position of your baby. 3D/4D bonding and fetal well being scan Ultrasound is the only non-invasive way to see a baby in the womb. Recent advances in imaging have resulted in the introduction of three-dimensional (3D) and four-dimensional (4D) ultrasound. Used in conjunction with traditional two-dimensional (2D) ultrasound, 3D/4D ultrasound provides more detail in “real” time, so your baby can be seen moving around. A 3D/4D ultrasound scan can be undertaken at any stage in pregnancy but the best time is between 26 – 32 weeks for the most realistic pictures. At this stage we will clearly be able to see your baby’s face, hands, fingers, feet and toes as well as any facial movements or gestures it may be making. Many parents-to-be have commented on the amazing quality of the pictures, even noting genetic similarities to family members. In this respect, the 4D scan has been shown to promote maternal and paternal bonding. There can be limitations sometimes with a 3D/4D scan. If there is inadequate amniotic fluid surrounding your baby, or if it has its face covered or is looking away, making it difficult to get a clear picture of the face. If we can’t get good pictures for you then we will rebook you or only charge you for a growth and well-being scan, which we would normally do anyway.

What will I experience during the examination? Your pregnancy scan will be performed by an ultrasonographer. The examination is performed with you lying on your back on a comfortable couch. Warm gel is applied to your abdomen and the transducer is placed on the skin and moved around to get good views of your baby. Wearing a loose-fitting two-piece outfit will mean you will not have to remove all of your clothes. In a few cases such as early pregnancy, an internal (trans-vaginal) scan may be the best method of seeing the baby. The procedure will be fully explained to you if you need to have this done. You will be able to watch your scan on the television monitor and the ultrasonographer will explain what can be seen. We will give you lots of pictures of your baby in different positions and if you would like us to, we are happy to provide you with a DVD recording or video recording.

How do I get the results? A report of the examination is given to you at the time of the scan, along with a verbal explanation of the findings.

Frequently asked questions? Do I need to fill my bladder for the scan? Only in very early pregnancy do you need to have a full bladder. In later scans it can be useful to have some fluid in your bladder so the birth canal can be seen. This does not have to painful for you. Do I need to be referred by a doctor? No. For all pregnancy scans you can self refer, however, it is advised that you inform your midwife or doctor that you are attending the clinic. In cases of pain and bleeding you should seek the advice of your doctor prior to attending. How long will the scan take? Usually the scan takes less than half an hour. However, the baby might not be in a good position to scan and therefore the examination will either take longer or we might need to examine you again after a short walk. How do I get my results? The ultrasonographer will give you a report of the examination at the end of the scan with a verbal explanation of the findings. At what stage can the fetus be sexed? The best time for determining the sex of the baby is from 20 weeks onwards. How can I book for the examination? You can ring the Kent Medical Imaging clinic on 01732 897666 to book an examination.