Miscarriage causes & recurrent miscarriage

Coping with miscarriage

Sadly, we know that miscarriage occurs in one in four pregnancies.  This is little consolation when you have lost a baby through miscarriage, and you may want to find out why it occurred and if you can reduce the risk of it happening again.

The vast majority of patients who have experienced a miscarriage will go on to achieve a healthy family, so it’s important to stay positive. However, a small percentage of couples will experience more than one consecutive miscarriage. If you have three or more consecutive early pregnancy losses this is called recurrent miscarriage, and affects about 2% of women trying to have a baby.

What causes a miscarriage?

Some of the causes of miscarriage include:

  • Random chromosome variations
  • Genetic variations
  • Parental chromosome variations
  • Uterine variations
  • Immune causes
  • Blood clotting disorders
  • Other medical conditions
  • Hormone imbalances

Age is also an important factor. After a woman has turned 43, there is a 50% chance a pregnancy will spontaneously miscarry. Dr Iris Wang, fertility specialist with IVFAustralia, explains the common misconceptions around miscarriage and why they occur on our Fertile Minds YouTube Channel:


What causes a miscarriage? - Fertile Minds Video

Hi there. Thanks for watching. I'm Dr. Iris Wang from IVFAustralia, and I'm talking to you from my office in Chatsworth on the northern suburbs of Sydney. What I'd like to do is have a chat about miscarriages today.

Unfortunately, this is a very common event. But I hope after watching, you'll feel reassured that most people who suffer miscarriages will go on to have a healthy family. It's important to stay positive. Now, just to put it into a bit of perspective, 15 to 20% of all recognised pregnancies will end as miscarriages. It is indeed very common. There is certainly a lot of misconceptions out there, but miscarriages usually have nothing to do with general lifestyle events, such as moving house, lifting heavy boxes, work stresses, personal life stresses, exercises, or traveling. None of those. The majority of miscarriages are related to genetic abnormalities of the embryo.

The genetic materials are contained in the structures called chromosomes. Some bits may be missing or there may be too many copies of another one. These may be incompatible with life, therefore, miscarriages. These events are random, but they can be related to egg or sperm quality. A woman's age heavily influences the risk of miscarriages because, as we all know, egg quality declines with age. There is nothing we can do about age, right? We all age. But there are potentially treatable causes for miscarriages and they are anatomical, hormonal, autoimmune and genetics.

I'll just give you some examples here. Let's say a fibroid, that grows inside into the cavity of uterus can potentially affect implantation, is an anatomical cause for miscarriage. And thyroid gland, prolactin gland abnormalities are hormonal causes for miscarriages. And for autoimmune causes, say antiphospholipid syndrome. It's not very common, but certainly a well-recognised cause for late miscarriages.

And then, even less common are genetics causes. Now, here I'm talking about all the genetics of the parents, not the embryo. An example will be balanced translocation. Us doctors will go looking for these causes and treat accordingly. But the unfortunate effect is 50% of couples who suffer recurrent pregnancy loss have no cause found. This is the bad news. But the good is, even after three consecutive miscarriages, the chance of everything being perfectly normal the next time is still close to 17%. This is still very good, and that's why I'm saying we can afford to be positive.

And for these people, there is nothing to treat. But even close monitoring, we've found, which is series of ultrasounds and hormonal assessment, have been found to improve outcome. Don't ask me why, but the data is there. If anything, at least we collect a bit more information about this patient, about the pregnancy, and potentially this could help with subsequent care, even if that pregnancy failed.

What I like to do now really is to finish with a bit of a story about this lady I met 30 years ago. I was very junior in my training at the time, and I was doing some research and I approached this lady as a potential subject for my study. Now, she just had a baby and I found out that this was the first successful pregnancy she's had after 13 miscarriages, and I'm not exaggerating. And her problem was balanced translocation. Now, without going into too much detail, it basically means she's got genetic material on her chromosomes, where the positions are swapped from chromosome to another chromosome. For her, she's got all the genetic material she needs and so she's perfectly normal. But when she reproduces, she'll split her chromosomes in half and passes them on to the child, because the partner contributes the other half.

And when that happens, there's a 50/50 chance she ends up passing an unbalanced lot of chromosomes to the child. Again, incompatible with life and, therefore, miscarriages. Now, this was a late 1980s so we didn't have the kind of genetic testing we have nowadays. And we really take it for granted nowadays that we can just do IVF, screen the embryo for genetics and put the normal embryo back and, therefore, reduce the chance of miscarriages and lead her to a success much earlier. But, for her, all she could do in those times was just keep trying. And even for something that was 50/50, it took her 14 goes. And also probably, presumably, not all of the miscarriages were related to this balanced translocation, and it also reflects the kind of complexity of miscarriages. And, also, I think this story tells you how far we've come in a few decades from not being able to test embryo to being able to do a lot testing the embryo. I think my main message for people out there is you need to stay positive because we do have statistics that tell us we can afford to do so.

Here in IVFAustralia, we're able to offer you the genetic testing for embryos to minimise the pregnancy loss related to chromosomal abnormality. Since I've already said, that's the commonest cause for miscarriages. What we do is that we will do an IVF cycle and the eggs will get fertilised and they get grown to day five. That helps us to identify the best embryos. They are called blastocyst by day five. When they're that good, they have good options of being able to succeed for pregnancy. And we will then biopsy those embryos, taking a few cells out of that particular embryo, and we test the chromosomes of that particular embryo.

Now, on day five, we won't get a result so we have to freeze that embryo. Usually about 10 to eight days later, we get a result back. And all of these embryos are labeled one, two, three or four, so we'll have the result one is normal, two maybe abnormal and so on and so forth. In a frozen embryo thaw cycle, we will then put the normal embryo back to the uterus and hopefully improve the success rate, minimise the miscarriage risk. It is certainly something that is taken up quite often by our patients who are 37, 38 onwards.

If you've experienced a miscarriage or you're going through a cycle and concerned about losing a pregnancy, we're here to help you. We have a team of very qualified counsellors and they are here to help you through this difficult emotional journey.

Do give us a call. We have a 1-800 number and you can also find a lot of information about us on our website. Okay. I hope you find this chat helpful to you. And I certainly want to thank you once again for watching. For now, be safe, be well and bye for now.

*All opinions expressed on the Fertile Minds YouTube Channel belong to the individual doctors, scientists and specialists, not the Virtus Health group.

Chromosomal variations - genetic problems with the embryo

One of the most common reasons why IVF is unsuccessful, or why miscarriages occur, is because of chromosomal variations in the embryo.

Up to 70% of embryos, whether created naturally or through IVF, are lost before birth. This usually occurs within the first three months of pregnancy, most often before implantation.

What is a chromosome?

A human cell contains genetic material arranged in dense strands, called chromosomes. A normal cell will contain 23 pairs of chromosomes. Fertilisation combines 22 chromosomes and an X chromosome from the mother’s egg with 22 chromosomes and either an X or Y chromosome from the father’s sperm. An embryo then has 46 chromosomes – if it’s a female, with two X chromosomes, and if it’s a male, with an X and a Y chromosome.

If the cells of an embryo contain the wrong number of chromosomes this is called aneuploidy, and causes the embryo to develop abnormally. Women over 38 years of age are at greatest risk of conceiving a baby with a chromosomal variations.

Sometimes pieces of chromosomes break off and attach to the ends of other chromosomes. You would then have a normal number of chromosomes (known as balanced translocation), but your children may inherit the chromosome with one part missing, or the chromosome with an extra part (unbalanced translocation). Embryos with unbalanced translocations will usually miscarry or fail to implant.

Dr Leeanda Wilton leads our Pre-implantation Genetic Testing (PGT) team. She found that testing for only 8 to 9 chromosomes in an embryo is inadequate, as up to 30% of embryos thought to be normal had an error (chromosome variation) on another chromosome that they were not able to test. Our pioneering research in this field has resulted in a new approach to testing for chromosomal variations, Advanced Embryo Selection.

Testing for genetic diseases

A gene is a sequence of DNA (genetic material) on a chromosome with a particular function. Humans have up to 20,000 different genes. When the DNA sequence on a particular gene is altered, a genetic variation such as cystic fibrosis or thalassaemia may result. It is now possible to test embryos for many single gene disorders or chromosomal variations with Pre-implantation Genetic Testing (PGT).

Some of the most common conditions tested for include:

•    Huntington's disease (direct and exclusion)
•    Cystic Fibrosis
•    Thalassaemia
•    Duchenne muscular dystrophy
•    Fragile–X
•    BRCA1/BRCA2 (hereditary breast / ovarian cancer)

IVFAustralia's miscarriage care program

Our clinicians are specialists in reproductive issues, and have expertise in managing early pregnancy care. This includes a thorough medical assessment and treatment plan for concerns about miscarriage.

IVFAustralia’s Miscarriage Care Program provides support for couples who have experienced the distress of miscarriage, and includes:

  • Initial testing to investigate any cause for the miscarriage, particularly if it has happened more than once
  • Specialised care during the next pregnancy, including blood tests, hormonal and ultrasound monitoring to provide reassurance throughout the first stages of pregnancy.

Advanced embryo selection

IVFAustralia, as part of the Virtus Health Group of IVF Clinics, and our sister clinic Melbourne IVF, has been involved in a scientific breakthrough with the world’s fastest and most precise embryo selection test.

By screening all chromosomes in a developing embryo we can select the embryo with the greatest chance of success. This can address some of the key causes of miscarriage, and give some certainty to couples who have experienced recurrent miscarriage.

Recurrent implantation failure explained

Recurrent implantation failure (RIF) is the failure to achieve a pregnancy following several cycles of IVF where three good quality embryos have been transferred.

Causes of recurrent implantation failure can include:

  • The quality of the sperm and eggs which is important for creating a healthy embryo. Factors including an unhealthy lifestyle and age can affect the quality of sperm and eggs. 
  • Chromosomal variations in the embryos
  • Structural, hormonal or immunological condition of the uterus

IVFAustralia can investigate all of these factors and work with you to discuss possible treatment options if recurrent implantation failure occurs.

Our quest to de-stigmatise miscarriage

At IVFAustralia, a member of Virtus Health, we want to help open-up conversations around miscarriage and de-stigmatise pregnancy loss.

We are the proud partners of a documentary available to watch on Stan, the Misunderstandings of Miscarriage, which follows Australian actress and filmmaker, Tahyna MacManus, on her four-year journey of pregnancy and miscarriage. Tahyna embarks on a quest to shed light on the physical, emotional and psychological impacts of miscarriage, as well as the lived experiences of other women in search of support and understanding.

Her quest didn't end there. Tahyna continued her quest to find out more about miscarriage by speaking to some of our fertility experts. We explore these questions together, including common myths around miscarriage, why miscarriages occur, what you as a partner can do to support each other, and advice for speaking about pregnancy loss with your friends or family members.

Miscarriage myths

Exploring 'The Why'

Finding support & speaking about miscarriage

Partner support