Miscarriage causes & recurrent miscarriage
Coping with miscarriage
Sadly, miscarriages are a common occurrence, with one in six pregnancies ending before week 20. 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.
- 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
• Duchenne muscular dystrophy
• 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.