Pregnancy - tests and scans

A range of tests are available if you are pregnant. These tests can confirm your pregnancy and also monitor your baby’s development in the womb. There are also optional tests that can provide information about whether a pregnancy is affected by a range of conditions.

Regular check-ups with your doctor or midwife are an important part of pregnancy care, including information and advice about what tests you and your baby will need.

The different kinds of tests available to pregnant women include tests:

• to confirm pregnancy
• to monitor the health of the mother and the baby
• maternal health screening
• for specific medical problems (screening and diagnostic tests).

Tests to confirm pregnancy

A missed menstrual period is usually the first sign of pregnancy. Tests to confirm pregnancy detect a pregnancy hormone called human chorionic gonadotropin (βhCG).

The various tests include:

• Home test kit – these are available from pharmacies. A typical kit includes special paper that is sensitive to the presence of βhCG in urine. It is important to use a home test kit according to the manufacturer’s instructions, or false results can occur. Always confirm your results with your doctor. Pregnancy tests taken by your doctor are rarely inaccurate.
• Urine test at the doctor’s office – the doctor can test your urine for βhCG.
• Blood test – a test of the βhCG levels in your blood can be accurate within one week or so of conception.

Prenatal tests to monitor the health of the mother and the baby

Pregnancy care involves regular appointments with your doctor or midwife to monitor your pregnancy and the baby’s growth. This includes tests that check on the health of both you and your baby, and help to identify any potential problems with the pregnancy.

Routine prenatal tests may include:

• Maternal health screening blood tests at different stages of the pregnancy, such as blood group, iron levels, checks for maternal diabetes, immunity to rubella and other infections.
• Ultrasound (first trimester) – a painless, non-invasive scan done within the first 3 months of pregnancy. This can be used to confirm the number of babies and helps to calculate the date you are due to give birth. This is known as your estimated due date.
• Ultrasound (second trimester) – this is usually performed between 18 and 20 weeks. It is used to check the baby’s development, and monitor the size and location of the placenta. The baby’s sex can often be determined (if you wish to know), although this may not be 100 per cent accurate.
• Ultrasound (third trimester) – in the last 3 months of pregnancy, an ultrasound may be offered to check the baby’s growth, fluid levels around the baby and the positioning of the placenta.

Tests for specific medical conditions in pregnancy

Tests for specific medical conditions (including Down syndrome, neural tube defects such as spina bifida, or genetic conditions known to be present in a family) are optional. A woman may or may not wish to proceed with these tests, and may like to discuss her options with her doctors or with a genetic counsellor before making a decision.

The Prenatal screening website brings together inform for health professionals and prospective families on screening, diagnostic testing and continuing or terminating a pregnancy

Screening tests and diagnostic tests in pregnancy

It is important to understand the difference between screening tests and diagnostic tests. Screening tests can provide information about how likely it is that a baby might have a particular health problem, but cannot provide a definite answer. For example, results from a screening test may suggest as increased chance or low chance, or provide an estimate of chance, such as one in 1,000.

A diagnostic test provides a more definite result.

Routine screening tests

Screening tests can provide an estimate of how likely it is that a baby is affected by a range of conditions but cannot make a diagnosis. If a screening test suggests an increased chance, further tests are available to confirm that result.

Examples of routine screening tests include:

• Combined first-trimester screening – this test combines information from a first-trimester ultrasound (for example, a measurement taken from the back of the baby’s neck known as the nuchal translucency) and a blood test from the mother (first-trimester maternal serum screening) to calculate the chance of a group of chromosome differences, including Down syndrome.
• Second-trimester maternal serum screening – this is a maternal blood test that helps to determine the chance of some conditions that may affect the unborn baby, such as chromosome differences (including Down syndrome) or neural tube defects (such as spina bifida).
• Non-invasive prenatal testing (NIPT, also known as cell-free DNA screening) – is a blood test that looks at the baby’s genetic material (DNA), which can be found in the mother’s bloodstream. It can provide information about the chance of conditions such as Down syndrome and some other chromosome differences, and can be done any time from 10 weeks into the pregnancy. It is more accurate than combined first-trimester screening or second-trimester maternal serum screening, but it is more costly than the screening tests.

To help you make decisions about what test(s) might be most suitable for you visit the YourChoice website.

Diagnostic tests

Some pregnancies are known to have an increased chance for a particular condition. For example, there may be a family history of an inherited disorder, or the mother may be older (we know that the chance of having a baby with a chromosome difference such as Down syndrome increases with age).

In other cases, a pregnancy screening test may have suggested an increased chance for a particular condition. A diagnostic test can provide more definite information about whether a condition is present. Some of these diagnostic tests use a needle to collect a sample of placenta or amniotic fluid and carry a small risk of complications including miscarriage.

Diagnostic tests include:

• Ultrasound– may be used to check the health of the baby in the case of unusual pregnancy symptoms, such as vaginal bleeding or lack of fetal movement.
• Chorionic villus sampling (CVS) – a test that checks for specific medical conditions by taking a sample of the placenta. The placenta was originally formed from the same cells as the baby, so testing a small sample of placenta can provide information about the baby. To collect the sample, the doctor inserts a slender needle through the mother’s abdomen. The needle is guided with the help of ultrasound. The tissue (known as a chorionic villus sample) is then examined in a laboratory.
• Amniocentesis – a doctor inserts a slender needle through the abdomen to withdraw a small amount of amniotic fluid, the fluid which surrounds the baby in the womb. This fluid sample contains some of the baby’s cells which have been shed as the baby grows, and these are then examined in the laboratory.

Making decisions about diagnostic testing in pregnancy

About one woman in 20 is told that there may be a complication in her pregnancy. As screening tests cannot provide definitive information, many women who have an increased-chance result on a screening test will go on to have a normal pregnancy.

The decision to have further tests to confirm whether a condition is present is up to the woman and her family after discussion with her doctor or midwife.

Diagnostic tests may be considered for a range of reasons. For example, if a diagnostic test confirms the presence of a medical condition:

• Some abnormalities can be surgically corrected while the baby is still in the uterus.
• A woman and her baby may need specialist care before, during and after at the birth.
• Knowing in advance that the baby has a particular condition may provide a family with time to prepare.
• Depending on the condition identified in diagnostic testing, some women or families may decide not to continue a pregnancy and arrange a termination of pregnancy (abortion).

Immunisations in pregnancy

Immunisation can protect you and your unborn baby against many infectious diseases. The seasonal influenza vaccine (often called the ‘flu shot’) is recommended and funded for all pregnant women under the National Immunisation Program. The flu shot is safe at all stages of pregnancy and provides protection for you and your baby for the first 6 months of their life.

The whooping cough combination vaccine (also known as the ‘three-in-one dTpa vaccine') is free for pregnant women from 20 weeks gestation. The vaccine immunises against whooping cough (also known as pertussis), diphtheria and tetanus.

You can get a COVID-19 vaccine if you are pregnant, breastfeeding or trying to fall pregnant.

Best Practice for Health professionals talking to families about screening and test results

Down Syndrome Australia conducted research into prenatal screening and found 49% of families felt pressure from their health professionals to terminate their pregnancy, 42% were given misinformation about Down syndrome and 45% felt they were not supported appropriately during their pregnancy.

It is essential that health practitioners provide families with accurate, balanced information pre and post prenatal screening and diagnostic testing, as well as time to make an informed decision.

Medical practitioners must also:

• Deliver high chance or confirmed diagnosis results using neutral language (e.g., ‘chance’ rather than ‘risk’, factual delivery of a diagnosis without emotive terms such as ‘I’m sorry’ or ‘bad news’).
• Provide up-to date, evidenced-based information on Down syndrome and other conditions being screened for, both before screening and after results are given.
• Offer referrals to peer support services such as local Down syndrome associations.
• Offer non-directive counselling and support services both before and after a decision is made on whether to continue the pregnancy.
• Give respect for decisions made by families, and not revisit that decision once it has been communicated, while making it clear that they have a right to change their mind.

Where to get help

• Your GP (doctor)
• Down Syndrome Victoria
• Prenatal screening
• Midwife
• Obstetrician
• The Maternal and Child Health Line Tel. 13 22 29 (24 hours, 7 days)
• Genetic counselling services – available at many large metropolitan public maternity hospitals, or call Victorian Clinical Genetics Services Tel. 1300 118 247.
• Paediatrician
• Local hospital maternity service
• Pharmacist
• Sexual Health Victoria (SHV). To book an appointment call SHV Melbourne CBD Clinic: (03) 9660 4700 or call SHV Box Hill Clinic: (03) 9257 0100 or (free call): 1800 013 952. These services are youth friendly.
• NURSE-ON-CALL Tel. 1300 60 60 24 (24 hours, 7 days) – for expert health information and advice