It’s natural to want to find a reason or a cause for a miscarriage so you can try to prevent another. In most cases, we don’t know why miscarriage occurs, and it’s rarely caused by something you’ve done.
At a glance
- Depending on your miscarriage and circumstances you may be eligible to undergo testing
- There are a number of tests to check why your miscarriage may have occurred
- Genetic testing services are available throughout Australia
- Testing is not commonly offered unless you have experienced recurrent miscarriage (3 in a row).
In Australia, testing for the cause of miscarriage is not generally offered unless you have experienced recurrent miscarriages (3 or more miscarriages in a row) or if you have a personal or family history of a condition that may impact your pregnancy. While testing can be done to try and work out why you have experienced a miscarriage, unfortunately, it is not always possible to find out the cause.
Below are some of the things your doctor may order to test for:
Blood clotting disorders
Antiphospholipid antibody syndrome is a blood clotting disorder. It develops when your immune system makes abnormal antibodies in the blood which then increase the risk of blood clots and pregnancy problems such as complications in placental formation and function. Research has found high levels of these antibodies in up to 15% of women who experience recurrent miscarriages.
Treatment for antiphospholipid antibody syndrome is available. If you are diagnosed with a blood clotting disorder, your specialist will go through options that may work for you.
If you are rhesus negative (meaning you have a minus sign following your blood type, for example, A-) and experience a miscarriage, you may be prescribed anti-D injections. This procedure prevents complications for future pregnancies if your next baby is Rhesus positive.
Around 50-80% of miscarriages are due to chromosomal abnormalities. The vast majority are due to spontaneous chromosomal abnormalities in the parents’ sperm or egg and only a very small number to hereditary abnormalities. The older you and your partner are, the higher the risk of abnormalities.
If you have experienced recurrent miscarriage your doctor may refer you and your partner to a genetic counsellor to discuss and test for any potential genetic risks or abnormal foetal developments (heart defects, chromosomal abnormalities, spina bifida). Finding out that you have experienced miscarriage due to genetic reasons can be very distressing. A genetic counsellor can help you assess your risk of genetic disorders in future pregnancies and how you might decide about future pregnancies.
Cervical weakness, also known as an ‘cervix insufficiency’, occurs in less than 1 in 100 women. If you have experienced late miscarriage or premature labour due to your cervix opening too early, you may have a weakened cervix. A weakened cervix can result from previous pregnancies, anatomical abnormalities that you may have been born with, particular health conditions, a history of having surgical or medical procedures involving your cervix, or a short cervix.
You may be referred for a scan to check the length of your cervix and if diagnosed, you may be advised to take progesterone or have a cervical stitch.
Abnormally Shaped Uterus
Some women have an abnormally shaped uterus. For some women this isn’t a problem but for others it can lead to problems during pregnancy or other reproductive difficulties. Having an abnormally shaped uterus can also increase the risk of miscarriage and premature birth depending on the abnormality. An ultrasound scan can be done to check whether you have an abnormally shaped uterus and if so, whether treatment such as surgery is an option.
Fibroids are common and do not usually cause any issues. However, large fibroids that impact the uterine cavity may increase your risk of miscarriage.
Polycystic Ovary Syndrome
There is evidence to suggest PCOS may be associated with an increased risk of miscarriage. Polycystic ovary syndrome, commonly referred to as PCOS, is a common hormonal condition affecting around 15% of women of reproductive age. Women with PCOS often have enlarged ovaries and many small cysts or follicles which fail to mature or produce eggs that can be fertilized when released from the ovaries. PCOS is one of the leading causes of infertility in women and is also associated with a range of symptoms.
If you are concerned about PCOS it’s best to see your doctor who may discuss your symptoms and medical history with you, examine you and may order some blood tests and an ultrasound to determine whether you may have PCOS.
Uncontrolled Diabetes and Thyroid Problems
Uncontrolled diabetes and untreated thyroid problems are associated with an increased risk of miscarriage. The thyroid and having healthy levels of the hormone it makes plays a critical role in supporting pregnancy. If your thyroid levels are too high or too low it can cause pregnancy problems. Thyroid function can be checked through a blood test which measures your thyroid hormone levels and thyroid stimulating hormone in your body. In most cases, thyroid problems are relatively straightforward to treat.
Endometriosis and hyperprolactinemia can also impact your hormonal balances and your pregnancy. Endometriosis does not cause miscarriage.
Infections and Food Poisoning
Some infections and food poisoning can cause or increase the risk of miscarriage. Infections include genital infections and sexually transmitted infections, rubella, cytomegalovirus, toxoplasmosis, listeria, salmonella and parvovirus.
Your doctor or specialist may suggest undergoing genetic testing if you have experienced an abnormal pregnancy or experienced recurrent miscarriages. Finding out that you have experienced a miscarriage due to genetic reasons can be very distressing. It is essential to discuss this with a genetic counsellor who can help you assess your risk of genetic disorders in future pregnancies and how you might decide about future pregnancies.
If you are looking for assisted reproductive clinics and fertility specialists in your area, speak to your doctor or Specialist or search:
It is important to remember that while testing can be done to try and work out why you have experienced a miscarriage, unfortunately, it is often not possible to find out the cause.
This section contains some graphic descriptions of what you might see during a miscarriage