Common Tests During Pregnancy

When you are pregnant you’ll find you need all sorts of tests. Many are specific to pregnancy, so it’s unlikely you’d need the same types of tests done at any other time in your life. All are designed to monitor your own, as well as your baby’s health.

Common tests during pregnancy also screen for and diagnose problems or conditions.

First Things First

The first test you’ll have when you are pregnant is, unsurprisingly, a pregnancy test. Confirming your pregnancy is the first step and from that, other tests will follow.

Most women make their own diagnosis of pregnancy by doing a home pregnancy test. This detects the presence in urine of a specific pregnancy hormone, Human Chorionic Gonadotrophin or hCG for short. If you go to a doctor or nurse to have your pregnancy confirmed, they’re likely to also test your urine and perhaps also order a pregnancy blood test.

Read the Instructions!

It is important to very carefully follow the manufacturer’s recommendations for home pregnancy testing. And to follow up a home pregnancy test with a visit to your GP. It is possible to have a false negative test, but very rare to have a false positive. Your GP will guide you about the next steps you’ll need to take.

A blood test can also check for the presence of hCG. This can be as early as one week after conception.  Blood results can take longer to get back than a urine pregnancy test which is almost immediate. You will need to see a healthcare professional (e.g. your GP) if you choose to have a blood test.

Tests Monitor the Health of a Mother and Her Baby

Pregnancy care involves regular appointments with your doctor or midwife. Antenatal care will include examinations and tests to check on the health of both you and your baby.  They will also help to identify any problems with the pregnancy or your baby.

Tests done during pregnancy fit into two categories: screening or diagnostic tests. Screening tests check for the risk or chances of the baby having a particular problem or condition.  Diagnostic testing checks for the definite presence of a condition and helps with diagnosis.

Who Will Order my Pregnancy Tests?

This depends on where you are going for your maternity care. If you’re attending a maternity hospital, the doctor or midwife you are seeing will order them. If you’re going to your GP or (private) obstetrician, they will order your tests. If you’re seeing a midwife for your antenatal care, they will order your tests. You’ll be told where you need to go for collection of blood or samples and what’s involved.

Where Will My Tests Be Done?

Some simple tests may be done during your pregnancy checkups with your midwife or obstetrician. Being weighed is a form of simple testing; so is checking for sugar or protein in your urine and having your blood pressure checked. For more complex tests, you may need to go to a pathology clinic to have blood collected or to drop off a urine sample.

If you are going to a maternity hospital for your pregnancy checks, there will be a pathology service located there. Private pathologists operate in-hospital clinics and within suburbs. Large maternity hospitals generally have an X-Ray department - this is where your ultrasounds will be done.

Common Pregnancy Screening Tests

You will have regular antenatal appointments throughout your pregnancy. Both you and your baby will be monitored for any problems, so it’s important that you keep seeing a health professional who is trained in pregnancy care.

• Blood tests will be done routinely throughout your pregnancy. At a first visit, it’s common to have a blood test that checks a mother’s blood group, her iron levels and any infections and immunity to certain diseases. Also included is a check for Diabetes.
• You are likely to have an ultrasound in your first trimester (3 months). This will check your baby’s size and helps to estimate their due date. The ultrasound will also give important information about the position of the baby, how many babies are present and if there are any early problems with their development. During this ultrasound, a measurement is taken from the back of the baby’s neck (nuchal translucency). Combined with specific blood results (from the mother), the risk of having a baby with Down syndrome is assessed.
• A second trimester ultrasound (between 18-20 weeks) will give more detailed information about the baby’s gender, development and size. It will also check for abnormalities. A second trimester blood test will also help to check for other chromosomal conditions.
• A third trimester ultrasound will again, check the baby’s growth, the position of the placenta and the baby’s position. Not every woman has an ultrasound in their last trimester but you may choose to have one for peace of mind and reassurance.
• A new type of DNA screening test, the Non-invasive Prenatal Testing (NIPT or cell-free DNA testing) checks the mother’s blood for her baby’s genetic information. Chromosomal abnormalities can be checked as early as 10 weeks gestation. Currently, NIPT is more expensive than other screening tests but is said to be very accurate.

Pregnancy Diagnostic Tests

When there is concern that a mother has a higher risk than average of having a baby with a specific condition, diagnostic testing is often done. For example, older women are more at risk of having a baby with Down syndrome. If a pregnancy screening test has detected problems, then diagnostic testing is recommended to give a definite diagnosis.

• Some diagnostic tests involve the mother having an amniocentesis. This means a sample of the placental cells and/or amniotic fluid is collected and examined.

Amniocentesis carries a risk of miscarriage.  This is why there needs to be a valid reason for having it done.

• Chorionic villus sampling (CVS). A few cells of the placenta are collected and examined in a laboratory. Chorionic villi are formed very early on in pregnancy and carry the same genes as the baby.  A range of genetic conditions can be diagnosed with CVS.

Do I Have to Have Pregnancy Screening or Diagnostic Testing Done?

You do not have to have any testing if you choose not to. However, it is very strongly advised that you do. Even if you don’t have a family history of having any problems, this is not an accurate indicator that you won’t. Around one in every 20 women will have some form of pregnancy complication.

Discuss your concerns with your partner, your family and your maternity care provider.

Benefits of Having Pregnancy Screening Tests

• Early detection can mean a better outcome for a mother and her baby.
• Some abnormalities can be treated while the mother is still pregnant. Intrauterine surgery on an unborn baby can change its prognosis.
• Specialist care can be arranged.
• Early detection can allow for better planning and parents coming to terms with having a special needs baby.
• Early diagnosis can give a couple time to make their own informed decision about whether they want to continue with the pregnancy or for the woman to have a termination.

It’s Worth Remembering

Not all problems can be diagnosed with testing. Although we’ve come a really long way in detection and diagnosis, there is no 100% guarantee of a test’s accuracy. Some families carry a genetic condition, increasing their risk of having a baby with a similar condition.

If you are concerned, it is important that you speak with your maternity care provider about your individual risk profile. Sometimes it’s necessary for couples to see a genetic counsellor before they conceive or early in the pregnancy.

About the Author:

Jane Barry has qualifications in general, paediatric, immunisation, midwifery and child health nursing. She holds a Bachelor Degree in Applied Science (Nursing) and has almost 30 years of specialist experience in child health nursing. She is a member of a number of professionally affiliated organisations including AHPRA, The Australasian Medical Writer’s Association, Health Writer Hub and Australian College of Children and Young People’s Nurses.