Understanding Pregnancy Scans and Tests in Australia
Pregnancy is a remarkable journey, and as expectant parents, understanding the various tests and scans available during this time can be overwhelming. In Australia, a variety of tests and scans are routinely offered throughout pregnancy. While these diagnostic tools can be beneficial in monitoring the progress of a pregnancy, they also come with their own set of risks, benefits, and controversies.
Ultrasound Scans
Ultrasound scans are one of the most common, widely used tools during pregnancy. They use high-frequency sound waves to create an image of the baby and the uterus, allowing healthcare providers to monitor the baby’s growth and detect any potential issues.
Types of Ultrasound Scans
- Early Pregnancy Ultrasound (6-8 weeks): Used to confirm the pregnancy, check the baby’s heartbeat, and determine the due date.
- Dating Ultrasound (7-12 weeks): This scan provides a more accurate estimate of the baby’s gestational age.
- Morphology Scan (18-20 weeks): A detailed scan to check the baby's physical development and detect any abnormalities in the baby’s organs, heart, and limbs, it aims to detect structural abnormalities, which may be found in about 2–3% of pregnancies. Can help identify conditions that may be isolated or part of a genetic syndrome or chromosomal abnormality.
- Growth Scan (after 28 weeks): Performed if there are concerns about the baby’s growth or position of both the baby or the placenta.
Benefits of Ultrasounds
- Early Detection of Complications : Ultrasounds can detect conditions such as ectopic pregnancies, multiple pregnancies (twins or more), and issues with the placenta, chromosomal or growth abnormalities. The facilitation of termination of a pregnancy can be assisted should this be considered appropriate by the couple.
- Monitoring Baby's Growth: Routine ultrasounds can assess the baby’s growth, development, and position in the womb, which is crucial for identifying complications like restricted growth. Facilitation of referral to a tertiary centre for evaluation should abnormalities be found.
- Enables access to a comprehensive care pathway when concerns arise, including multidisciplinary counselling with specialists (such as neonatal surgeons and geneticists), invasive fetal testing (like amniocentesis for genetic evaluation), and further imaging such as MRI or follow-up ultrasounds as needed.
- Safe and Non-Invasive: Ultrasounds are widely considered safe, as they don’t use radiation, making them a preferred method for monitoring during pregnancy.
Risks and Controversies
- Accuracy: While ultrasounds are generally accurate, they are not foolproof. In some cases, conditions can go undetected, false positives can occur or abnormalities can be detected, while the underlying condition remains unclear leading to unnecessary anxiety.
- Potential Overuse: Some argue that ultrasounds are overused in pregnancy, especially routine scans that may not be necessary for low-risk pregnancies. This could lead to unnecessary interventions or anxiety for expectant mothers.
Blood Tests
Blood tests are an essential part of pregnancy care in Australia, as they help to screen for various health conditions that could affect the mother or baby. These tests can provide valuable information about a pregnant woman's health and the baby’s development.
At approximately 28 weeks gestation a repeat of the full blood count will be done primarily to screen for anaemia as well as an antibody screen, which may be repeated at 34-36 weeks gestation in women who are rhesus negative. Often the Glucose tolerance test will be performed at the same time.
Common Blood Tests in Pregnancy
- Early Pregnancy Blood Tests: These tests are used to check the woman’s blood type, iron levels, and hormone levels (such as hCG and progesterone), which are important for a healthy pregnancy.
- First Trimester Screening (Nuchal Translucency Test): Typically done between 11-14 weeks, this involves blood tests and an ultrasound to assess the risk of the baby having chromosomal conditions like Down syndrome.
- Gestational Diabetes Screening: Usually conducted between 24-28 weeks, this test measures blood sugar levels to detect gestational diabetes, a condition that can affect both the mother and baby if left untreated.
- Blood Group and Antibody Screen: This test checks the blood type and whether the mother has antibodies that could affect the baby, especially in cases of Rh incompatibility.
Benefits of Blood Tests
- Early Detection of Health Issues: Blood tests can detect infections, iron deficiencies, or signs of gestational diabetes that could affect the mother and baby.
- Screening for Chromosomal Abnormalities: Tests like the Nuchal Translucency Test can help assess the risk of conditions such as Down syndrome early in pregnancy, allowing parents to make informed decisions.
- Preventing Complications: Early detection of conditions like anemia or gestational diabetes can help manage complications and improve pregnancy outcomes.
Risks and Controversies
- False Positives: Like ultrasounds, blood tests are not always 100% accurate, and a positive result doesn’t necessarily mean the baby has a condition. False positives can lead to unnecessary testing and emotional stress.
- Ethical Concerns: Some people question the ethics of certain screenings, particularly tests for chromosomal abnormalities, as they may lead to difficult decisions, including abortion.
Glucose Tolerance Test (GTT)
The Glucose Tolerance Test (GTT) is used to screen for gestational diabetes, Gestational diabetes is defined as women having a carbohydrate intolerance of varying degrees, that is first identified during pregnancy. This test involves drinking a sugary solution and having blood drawn at intervals to measure how the body handles glucose. If you want a more comprehensive discussion around this test check out our blog post here.
Benefits of the GTT
- Early Detection of Gestational Diabetes: Gestational diabetes can lead to serious complications for both the mother and baby, including large birth weights, preterm labor, and high blood pressure. Detecting it early helps manage the condition and improve outcomes.
- Better Management: If gestational diabetes is detected, it can be managed through dietary changes, exercise, and in some cases, medication, helping to reduce risks for both mother and child.
Risks and Controversies
- False Positives/Unnecessary Treatment: Some argue that the GTT is overused, and many low-risk women may receive unnecessary treatment if they test positive for gestational diabetes, especially if the test result is a false positive.
- Discomfort and Inconvenience: The GTT can be uncomfortable for some women, as it involves fasting and drinking a sugary solution, followed by multiple blood draws. Some may find the test challenging or even distressing.
Amniocentesis and Chorionic Villus Sampling (CVS)
Amniocentesis and CVS are invasive tests that are performed under ultrasound guidance and can be used to diagnose chromosomal conditions like Down syndrome. these test may be offered is abnormalities have been detected on other scans such as the morphology scan. Amniocentesis is typically performed later in pregnancy- from 15-16 weeks onwards, while CVS is done earlier -around 11 weeks but up to 15 weeks-16 weeks. The CVS test is done either vaginally or abdominally and amniocentesis test is done trans abdominally, where approximately 30mls of fluid is taken.
Benefits of Amniocentesis and CVS
- Accurate Diagnosis: These tests can provide definitive information about chromosomal abnormalities or genetic conditions, which is invaluable for parents making decisions about their pregnancy.
- Early Detection of Serious Conditions: Amniocentesis and CVS allow for the early detection of conditions such as Down syndrome, cystic fibrosis, and other genetic disorders.
Risks and Controversies
- Miscarriage Risk: Both tests carry a small risk of miscarriage (around 1 in 100 for amniocentesis and 1 in 200 for CVS), which is a significant concern for many expectant parents.
- CVS can result in crampy period like pain or spotting, additionally, cells from both the placenta and fetus is taken, therefore mistake that are identified may be limited to the placenta only and may not represent the fetus .
- Ethical Dilemmas: As with other prenatal tests, amniocentesis and CVS raise ethical concerns, particularly around the decision-making process if a serious condition is diagnosed.
Making Informed Choices
Pregnancy tests and scans are important tools in monitoring maternal and fetal health, however they do not have to be essential. It is important for expectant parents to be informed about their options, make their own choices and do what is right for them. While these diagnostic tools offer clear benefits, they also come with risks and potential controversies. It’s crucial to have open discussions with your healthcare provider about which tests and scans are appropriate for you based on your health, risk factors, and personal preferences. It is important to consider your own religious or cultural views and values, the impact these test and there results may have on your family as a whole, any prior pregnancy complications you may have had, any potential risks to you or your baby or any long term complications.
If you’re an expecting parent, talk to your healthcare provider about any questions or concerns you may have regarding pregnancy tests and scans and remember there is plenty of support options available to you to help with any decisions you may have to make.
If you gave any questions or concerns about any of this information please contact us on 0405 640 786 and remember this blog does not cover every topic.