The morphology scan, also known as a 19–20-week anatomy or anomaly scan, is considered to be part of the routine obstetric care that all patients should receive.
This scan will assess:
- Age of pregnancy/size of the fetus.
- The number of babies in the uterus.
- Baby’s physical development and anatomy, which involves looking at 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 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.
It is important to know that ultrasound does not detect all abnormalities. Many congenital heart abnormalities are complex and not visualized (seen) at the morphology examination. Sometimes, the view of the fetus may be limited by the fetal position or movement during the examination. Maternal obesity may limit visualization of the baby, and in some instances, the patient may be rebooked for further assessment.
In some circumstances, fetal abnormalities may not be seen on ultrasound despite a clear view. In some conditions, abnormalities only become evident later in pregnancy, or where there are 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 where an internal or transvaginal ultrasound may be necessary. Transvaginal ultrasound involves placing a thin transducer (slightly thicker than a tampon) into the vagina. The transvaginal ultrasound can give extra detail as the transducer comes into close proximity to the uterus. Measurements of the cervix completed at the time of a morphology scan are also generally 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 pregnancy.
Your examination will be done by a sonographer who will introduce themselves and confirm your identity and the procedure you are having. A clear gel is applied to the skin over the lower abdomen/pelvis so the ultrasound probe can move easily over the surface of your skin. Occasionally, the fetus may be in a position that makes it difficult to scan. If so, you may be asked to lie on your side or go for a short walk to help it move into a better position. Though rarely, sometimes, it may be required to have a transvaginal ultrasound to better see the structures being scanned, or return later in the day or the following day to scan when the baby has moved into a better position.
We ask that you limit the number of people attending the exam; ideally yourself and a support partner. If you have young children, it may be a good idea to arrange child care for them, or if possible, have someone come along that can care for them in the waiting room. When the scan is complete, the sonographer may allow others into the room briefly to view the baby. It is Dr Jones and Partners policy that you do not take any video of the ultrasound examination and that all electronic devices are turned off. You can obtain images at the end of your examination in accordance with the Dr Jones & Partners multimedia policy.
If you wish to know the gender of your baby, please ask the sonographer during the scan. The morphology ultrasound is often the first time fetal gender can be seen, but you should be aware that assessment of the sex is not 100% accurate. Sometimes, the genitalia may not be visible due to fetal position. If you do not wish to know the sex of the baby, please tell the sonographer at the beginning of the exam.
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 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 (transducer) 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 10-15 minutes. If the examination is causing discomfort or you want the examination to end, please advise the sonographer.
Before your Scan
Ideally, book your appointment so that the procedure is done when you are 19 – 20 weeks pregnant.
If possible, please wear comfortable, loose-fitting clothing for easy access to your abdomen. Two-piece clothing is ideal (separate upper/lower garments).
Transabdominal: You will need a full bladder. Drink 500mL of water one hour before your appointment and do not empty your bladder (do not go to the toilet). Distension of your bladder provides a window to view your pelvic organs through and compresses bowel out of the way. Your bladder does not need to be so full that it causes you pain or distress; if this is the case, please tell reception staff on arrival, and they will talk to you about your options. If during the examination, your bladder is causing you discomfort, please tell the sonographer.
Transvaginal: If this imaging is needed, it is done on an empty bladder.
Preparation details for your examination will be confirmed when you make your appointment.
Approximately 60 minutes.
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