Ultrasounds in early pregnancy can be offered to confirm and accurately date a pregnancy.
***Key Points***
Ultrasounds in pregnancy and any antenatal screening tests are offered to all women but the choice is is your.
Your GP, Midwife or doctor will support and your family to make informed, independent decisions about what tests you have in pregnancy.
***Key Points***
***What is an ultrasound scan?***
What is an ultrasound scan?
An ultrasound scan is a procedure that uses sound waves to create an image or picture of your baby. An ultrasound in pregnancy is carried out by an obstetrician or a specialised health professional such as ultrasonographer. During the scan, gel is placed on your abdomen and a probe called a transducer is placed against your skin. Pulses of sound waves create echoes that are turned into images which you can view on a monitor.
Sometimes your doctor may suggest a transvaginal ultrasound to get better view of your baby because during this ultrasound the probe is closer to your uterus. In this case, you will be covered with a sheet while the probe is inserted into your vagina and you will view the images of your baby on a monitor.
Having an ultrasound is usually a pain free procedure for you and your baby and there is no research to suggest an ultrasound increases the likelihood of a miscarriage when carried out in early labour.
***What is an ultrasound scan?***
***What does an ultrasounds check?***
Ultrasounds are a simple and easy way to check how your pregnancy is progressing, and to provide helpful information on how your baby is developing. Generally they used for the following
- To confirm your pregnancy and check the number of babies
- To work out the age of your baby (dating scan)
- To check your baby’s growth and physical development
- To check your baby’s position in your uterus
- To check the position of your placenta and to check your cervix
- To monitor your placenta’s health and blood flow through the placenta
- To check the amniotic fluid around your baby
What routine scans might be offered during pregnancy?
***What does an ultrasounds check?***
Your doctor or midwife will discuss the ultrasounds that are recommended and available in pregnancy. They will discuss the reasons they are recommending any procedure, ultrasound or screening test but the choice is yours.
These are
***Dating scan***
This ultrasound is usually offered in early pregnancy around 7-9 weeks of pregnancy. This scan can date your pregnancy and estimate your baby’s due date. This may be especially important if you are unsure of your last menstrual period date.
An early dating scan can also confirm how many babies you are carrying, and check that your baby is growing in the uterus and not in one of the fallopian tubes, known as an ectopic pregnancy.
***Dating scan***
***Nuchal translucency***
This ultrasound is offered between 11 weeks, 3 days and 13 weeks, 6 days of pregnancy.
During a nuchal translucency scan a measurement is taken of your baby’s nuchal translucency — a fluid-filled space behind your baby’s neck.
Your nuchal translucency scan results can be combined with a blood test, (PAPP-A) usually done in weeks 10 to 12 of pregnancy, to form a ‘combined first-trimester screen’, or CFTS. The combination of this blood test and the ultrasound results can give a more accurate estimate of your risk of having a baby with a chromosomal abnormality such as Downs Syndrome.
This result will not give you a definitive answer but it will provide a report that give a low risk or a high risk of having a baby with Downs Syndrome or risk of other chromosomal abnormality.
The chances of having a baby with a chromosomal abnormality such as Downs Syndrome are greater the older you are when you get pregnant. However, anyone can have a baby with chromosomal abnormalities irrespective of age so screening is offered to everyone, but the decision to have the scan or tests is yours.
An alternative is to consider the Non Invasive Prenatal screening (NIPT) test. This is also known as the cell-free DNA testing (cfDNA) and is another option for antenatal screening test for chromosomal abnormalities. It is more accurate than a nuchal translucency scan or the combined screening test but it can be more expensive as in Australia this is not funded by Medicare.
Some women choose not to have any tests or decide to have a diagnostic test instead such as chorionic villus sampling or amniocentesis which can give them more definite information about their baby’s health. We have a separate content page about these tests.
***Nuchal translucency***
***Morphology scan***
A morphology scan (also known as a ‘fetal anomaly scan’) is an ultrasound offered between 18 and 20 weeks of your pregnancy. This scan check for major physical abnormalities in your baby body organs.
This will check your baby’s heart rate and rhythm, check the location and function of your placenta and can reveal the sex of your baby if you wish to know.
***Morphology scan***
***Other scans***
For some women your midwife or doctor may recommend a third trimester ultrasound scan to assess your baby’s wellbeing and growth and the location and function of your placenta and cervix.
Do I need to have ultrasound scans?
Your doctor is likely to recommend you have one or more ultrasound scans during your pregnancy so they can check how your baby is developing, but you’re still free to choose whether or not you have the scan.
***Other scans***
Talk to your doctor or midwife about tests and scans to understand why they might be offered to you.
Resources
https://ranzcog.edu.au/wp-content/uploads/2022/05/Prenatal-Screening-and-Diagnostic-Testing-for-Fetal-Chromosomal-and-Genetic-Conditions.pdf
