Pregnancy & Birth

Pregnancy scans and screens explained

Which scans and screening tests will you have to track the health of your bub? While some are a little more risky and invasive, most are extremely safe and highly recommended.

Over the next nine months, there'll be blood tests, urine tests and probably an ultrasound or two, as well as regular blood-pressure checks and those exciting moments when you hear baby's heartbeat and see pictures of your unborn bub.
There are also other tests to check for abnormalities in your growing baby. Here's a list of some of the scans and diagnostic tests you may be offered.
Early scan: 6 to 12 weeksAn ultrasound may be ordered by a midwife or doctor if you have no idea of the date of your last period. It may also be suggested if you have a history of miscarriage or you're experiencing pain or bleeding.
Anomaly scan: 18 to 20 weeksYour baby will be recognisably human by this scan (and you can even choose to have it done in 3D to really see the shape of things to come). Her organs will be checked for abnormalities and she'll be measured to find out if she's growing properly. The shape of your uterus and placenta will be checked. This scan can often detect the sex of your baby, but not to the extent you'd be confident enough to start choosing nursery paint colours.
Nuchal translucency: 11 to 13 weeksThis test looks at how much fluid has accumulated behind the baby's neck to determine the chance of Down syndrome. It's done by ultrasound and may be coupled with a blood test. The result will give you a risk ratio (such as 500 to one) of having a baby with Down syndrome; however 10-25 percent of cases will go undetected. If your risk ratio is high or you want more conclusive results, there are more accurate but invasive tests available (see Diagnostic Tests, below).
Maternal serum testing: 15 to 18 weeks
This is a simple blood test (on the mother) to see if the foetus has an increased risk of a chromosomal problem or neural tube defect. It only gives you a risk ratio and a high percentage of affected babies are missed. Out of 50 babies identified as having a problem, only one or two will eventually turn out to have an abnormality.
Before undertaking any tests that check for abnormalities, think about what you would do if the results were positive. Finding out about a complication before the baby reaches full term allows you to either prepare for it or consider having a termination.
Chronic Villus Sampling (CVS): 10 to 12 weeksThis test can detect Down syndrome and cystic fibrosis. A needle is inserted through the mother's abdomen to extract cells from the developing placenta. These show the genetic make-up of the foetus, and are examined for abnormalities. There's a one percent chance the procedure itself will cause a miscarriage.
Amniocentesis: 16 to 18 weeksAmniotic fluid is extracted via a needle through the mother's abdomen and examined for chromosomal or neural tube abnormalities and genetic disorders. Because the test is done later during pregnancy than CVS, decisions about whether to consider termination are more complicated. The test also carries a one percent risk of causing miscarriage.
If you're going to a midwives' clinic at a public hospital, tests will probably be done there for free. If you're seeing a private obstetrician, you'll go to a hospital or radiology practice where you'll be charged a fee. A proportion of those fees can be claimed on Medicare.

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