Tests During Pregnancy

What tests am I having and why?

In pregnancy, many tests are considered ‘routine’ and the standard of care and others are targeted specifically towards certain at risk populations. Below is a brief overview of common tests in pregnancy, although as always, your specific circumstances and preferences will be discussed prior to initiating testing.

We recommend patients undergo the following blood tests
  • Blood group and antibody screen (repeated at 28 weeks if you a “negative” blood group)
  • Full Blood Examination (to exclude anaemia and other blood conditions)
  • Iron and Vitamin D testing
  • Midstream urine specimen (to rule out a silent urinary tract infection)
  • Infectious diseases screening (including Hepatitis B, C, HIV and syphilis)
  • Assessment of immunity to Rubella and, if appropriate, Varicella
  • Random blood glucose, plus a formal glucose tolerance test for certain populations at high risk of diabetes (e.g. PCOS, past history of gestational diabetes, family history)
  • B12 and folate, if indicated

**Although it seems like a lot of testing, this can all be done on just a few millilitres of blood and be done concurrently. All tests have evidence to support them and we do not organise tests which we do not feel will benefit you or your baby. Many patients will have already had these performed by their GP before they even meet their obstetrician.

Screening for genetic abnormalities

This testing is completely optional and up to personal preference, and some patients will opt not to do any screening at all. We completely respect and honour these choices, however some other families are concerned about the risk of Down Syndrome and other chromosomal conditions, and wish to undergo testing in this regard. There are many options available and they vary in terms of accuracy and cost. Some can be performed at any stage in the pregnancy, from as early as 10 weeks, and others are confined to certain time periods or trimesters. These will be discussed in detail at your first antenatal appointment.

  • Many women, particularly if uncertain of their due date, will have an early dating or viability scan, at anywhere from 6 to 10 weeks. The remainder of the recommendation applies to single pregnancies only. If there are twins on board, expect scans to be more frequent.
  • 12-13 weeks: Nuchal translucency + early morphology scan (historically performed as part of the combined first trimester screen, this scan is still valuable, even if you have had an NIPT)
  • 18-20 week: Mid-trimester morphology ultrasound, assessment of cervical length and placental location
  • Growth or placental location scans later in the pregnancy, if indicated, usually in the third trimester
Later in pregnancy
  • Diabetes screening at 26-28 weeks is considered routine and recommended for all pregnancies. Gestational diabetes complicates more than 1 in 8 pregnancies and with diagnosis and appropriate management, can still result in excellent pregnancy outcomes. If you are considered ‘high risk’, you may be encouraged to have diabetes screening on more than one occasion in your pregnancy
  • Rechecking FBE (blood count), iron stores and vitamin D at 26-28 weeks (performed on the same blood sample as the diabetes testing)
  • GBS screening at 36/37 weeks (this is not a blood test, but is a swab from the vagina and perineum). GBS (group B streptococcus) is a bacterium commonly and transiently carried in the genital tract and while it causes no problems for the pregnant woman, can be transmitted to babies and cause infections to susceptible newborns.
  • We will also assess if your pap smear is due and if so, we are happy to arrange that for you. Pap smears are safe to perform in pregnancy.