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Tests during pregnancy

Several tests are performed throughout the pregnancy to ensure that both you the mother and your baby are doing well.

Initial tests
At the start of the pregnancy, it is important to have a blood test to make sure that you are fit and well. Your GP may already have arranged these tests and if so, please bring a copy of the results with you to your first visit.

  • A full blood count to check for anaemia (low iron) 
  • Your blood type and for blood antibodies
  • Tests for hepatitis B, C, syphilis and HIV are recommended as conditions may affect a baby
  • Checking your immunity to rubella (German Measles) and varicella (chicken pox)
  • A urine test to check for bladder infection
  • Vitamin D level
  • Sometimes a dating ultrasound is performed early in the pregnancy to confirm that all is well with your baby, and to check how far into the pregnancy that you are. This will be performed at your first visit with Dr Miller if you have not already had one.

Genetic screening

Early in the pregnancy, screening tests are available to see what the chances are that your baby may have one of the more common genetic problems like Down Syndrome (Trisomy 21). 

Whether or not you would like to do genetic screening is an individual decision, and Trent will discuss the options with you at your first visit. Testing can be perfomed as early as 10 weeks pregnant.

'Genetic screening' means assessing what the likelihood is of having a baby with a common genetic problem. A good results provides lots of reassurance and significantly reduces the chances of common genetic problems. An abnormal screening result does not say for certian whether there is a problem but indicates that further testing is required.

There are 2 types of genetic screening tests available.

Firstly, a nuchal translucency ultrasound. This is an ultrasound and a blood test performed at about 12-13 weeks of the pregnancy. It is a combination of a blood test looking at several hormones, and the development of the baby on ultrasound. It gives an estimation of the chances of having a baby with some of the more common genetic problems such as Down Syndrome. It also is a good opportunity to assess the basics of the baby's development. It is mainly targetted at testing for Down Syndrome and similar conditions, but sometimes less common genetic problems can also be suggested at this ultrasound. If there are any abnormalities, then further testing is usually required which might consist of 'non-invasive prenatal screening' or a 'CVS' or 'amniocentesis' (see below). The nuchal translucency ultrasound is the standard, traditional way of doing genetic screening, and is still the recommended option for initial genetic screening for the baby.

Secondly, non-invasive prenatal screening (NIPS) is a blood test that you have from about 10 weeks of the pregnancy. There are several different brands available, common ones are 'Harmony', 'Nest' and 'Generation'. This is a new DNA test where we can detect traces of the baby's DNA in your blood, extract this and work out what the chances are of the baby having some of the common genetic problems. It tests for Down Syndrome and also the next most common genetic problems (trisomy 13, trisomy 18, and sex chromosome problems). It is important to say that it does not test for all genetic abnormalities. The gender of the baby can also be determined with this testing. A normal result with this test is 99.9% reliable for not having a baby with Down Syndrome. An abnormal result usually means there is about an 80 to 90% chance of having a baby with Down Syndrome, and we would always confirm this by doing an amniocentesis or CVS.

NIPS is a bit more accurate than the NT ultrasound at testing for Down Syndrome and a few other genetic conditions, but the NT ultrasound can sometimes suggest other problems that NIPS does not test for. Current advice is to do the NT scan, and use NIPS as an 'optional extra' or to get further information if an abnormality is seen at the NT ultrasound. 


At around 18 and 20 weeks, an ultrasound is recommended to assess how your baby is developing. This is the main ultrasound during the pregnancy, and is the best time to examine the baby’s growth and development. Close checks are made of the baby’s heart, brain, spine and other internal organs. It is also an opportunity to discover the baby’s gender (if you want to know, just ask!). The location of the placenta (afterbirth) within the womb is also determined, which is important to know for labour and birth. A normal ultrasound at 18-20 weeks is reassuring that the baby is developing well. Despite everyone's best care however, a normal ultrasound cannot detect every abnormality and is not a guarantee of a perfect baby.

Further tests

At 26-28 weeks, we recommend a full blood count, and blood tests for antibodies and pregnancy diabetes. This blood test takes 2 hours, as the diabetes test involves an initial fasting blood test followed by a glucose drink and then a blood test 2 hours later.

In the last month or so of the pregnancy you will take a low vaginal swab yourself to test for a bacteria in the vagina called Group B Streptococcus (GBS). GBS is a normal vaginal bacteria in about 1 in every 5 women. For women who carry it, there is a 1 in 200 chance of the baby developing an infection shortly after birth. If you are a carrier of GBS, we recommend a dose of antibiotic (usually penicillin) during your labour, which is safe for both you and the baby.


Suite 7, Level 1
Hurstville Private Hospital
37 Gloucester Rd
Hurstville NSW 2220 


Phone:  (02) 9580 2255                  
Fax:  (02) 9580 2244