The morphology scan, also known as the 19-20-week (2nd Trimester) anatomy or anomaly scan, is considered part of routine obstetric care.
The purpose of the morphology scan examination is to assess:
- Age of pregnancy/size of fetus.
- Number of babies in the uterus.
- Baby’s physical development and assess anatomy. This involves a detailed examination of the baby’s head, brain, face, lips, heart, stomach, lungs, abdominal wall, kidneys, bladder, spine, arms, legs, hands and feet.
- Position of the placenta.
- The length of the cervix.
- The volume of fluid around the baby.
Ideally, the scan is done at 19-20 weeks of pregnancy when the structures of the baby are seen more clearly. Please use our Pregnancy Scan Calculator to help with your scan dates.
It is important to know that ultrasound does not detect all abnormalities. Certain congenital heart abnormalities are complex and not often seen at the morphology examination. In many instances, the view of the fetus may be limited by the fetal position or movement at the time of examination. Also, the tissue between the ultrasound probe and the baby, absorbs the ultrasound waves, so if a patient is overweight the fatty tissue of the abdominal wall may make visualisation of the baby difficult. In these circumstances the patient may be rebooked for further assessment of the fetus.
In some circumstances, fetal abnormalities may not be seen on ultrasound despite a clear view. This may be explained by the natural history of the condition where the abnormality only becomes evident in later pregnancy or where there are in fact no structural changes in the baby (e.g. cerebral palsy, biochemical abnormalities and some chromosomal abnormalities).
In most cases, the ultrasound will be performed transabdominally, but there are some situations when an internal or transvaginal ultrasound may be necessary. Transvaginal ultrasound involves inserting a thin transducer (ultrasound probe slightly thicker than a tampon) into the vagina to get more detailed images as the transducer is closer to the pelvic organs. This improves the accuracy of diagnosis. Measurements of the cervix at the time of the morphology scan are also sometimes performed transvaginally. A transvaginal scan is optional; it is your decision whether to have that part of the examination.
Transabdominal and transvaginal ultrasounds are safe at all stages of the pregnancy.
Before your scan
If possible, please wear comfortable, loose-fitting clothing that allows easy access to the area that is being imaged. Two-piece clothing is ideal (separate upper/lower garments).
Please empty your bladder 2 hours before the examination time. Then slowly drink 600ml of water to fill your bladder and keep it full for your examination.
Morphology Scan Procedure
When you visit Adelaide Women’s Imaging for a Morphology scan you will be greeted by one of our friendly reception staff. A sonographer will then collect you from the waiting room and take you to the ultrasound room. The sonographer will perform an ultrasound of the abdomen (transabdominal ultrasound) detailing the fetal anatomy and maternal pelvic anatomy.
The sonographer will begin by asking you to lie on a bed next to the ultrasound machine. A clear gel is applied to your stomach. The ultrasound probe is then placed in contact with the skin and moved over the surface of the lower abdomen to study the baby below. The scan is completely painless, although pressure may be applied to improve view in some areas. The sonographer will take an initial set of images, that will be reviewed by the Adelaide Women’s Imaging obstetrician and gynaecologist. In some instances, a transvaginal (internal) ultrasound is undertaken to better assess the cervix and placenta. The sonographer will discuss this with you if this is necessary. Our doctor will perform a brief ultrasound assessment and discuss the results of the scan with you on the day in the ultrasound room. A detailed report will be sent to your referring doctor.
If you need a transvaginal ultrasound to measure your cervix or obtain better detail of your baby, you will be asked to empty your bladder and change into a gown. The transvaginal probe (transducer) is disinfected, and a protective cover is placed over the transducer each time it is used, so there is no risk of infection. The probe is lubricated with gel prior to insertion into the vagina and then moved gently to see the structures required. This part of the examination generally takes 5 minutes. If the examination is causing discomfort, please advise the sonographer.
Approximately 60 minutes.
Frequently Asked Questions
Can every defect of the fetus be seen?
No, a normal ultrasound examination cannot guarantee a normal fetus. Unfortunately, there are still a few anomalies, which cannot be seen. We cannot see chromosome abnormalities but may see changes indicating a higher likelihood of chromosome abnormality.
Can I find out the sex of the baby?
Often the sex of the baby can be seen. There are times when due to foetal position it cannot be seen.
Can I have a photo or DVD of the images/scan?
The MyAWI app will have all your scans uploaded so that you can easily view all images of your baby on a smart device at any time.
What is the risk of the scan?
All ultrasound examinations are a safe investigation at any stage of the pregnancy.