My mother had multiple miscarriages, will I?
When someone is planning for or is currently pregnant, they start to think about their family history to figure what kind of experiences or health concerns they might have. If your relative, particularly your mother, had a history of multiple miscarriages, you may be wondering if you will have the same experience. In this post, we’ll discuss considerations and potential causes of recurrent miscarriage.
To start, healthcare providers such as a genetic counselor typically ask follow-up questions like:
How many miscarriages occurred, and during which trimester did they happen?
Were all the miscarriages with the same partner?
Was there an explanation provided for any of the miscarriages?
Was genetic testing conducted on the products of conception?
Were there any birth defects or physical differences noted for the babies?
Were there any health complications for the children born?
It is unlikely someone will have the answers to these questions, not only because discussing miscarriage can be emotionally charged but also because, in the past, there was stigma attached to its occurrence. Additionally, limited knowledge or assessment was done when someone experienced a miscarriage, and this is still often the case now.
While these answers may guide a possible hypothesis for causes, it can be challenging to pinpoint the exact reason for someone's history of multiple miscarriages, and there may be multiple reasons. Even if there is a suggestive cause, confirming it without follow-up for the previous losses, which may or may not be available, can be difficult.
For miscarriages in the first trimester, half of the time, a chromosome abnormality is the underlying cause. Most chromosomal abnormalities are sporadic errors that occur and are not considered hereditary. However, if someone is experiencing multiple first-trimester miscarriages, they may have a chromosomal rearrangement.
To test if someone has a chromosomal rearrangement, a "karyotype" can be performed. The images below show karyotypes, which are snapshots of what the chromosomes look like under a microscope after being lined up and organized. A chromosomal rearrangement occurs when someone has the typical number of chromosomes, but they are arranged uniquely. This may involve a piece of one chromosome being attached to another, known as a translocation. Consequently, individuals with a chromosomal rearrangement have an increased chance of passing on chromosomal abnormalities during pregnancy, potentially leading to miscarriages.
Typical karyotype with chromosome pairs 9 and 11 emphasized. Chromosome 9 DNA is represented by the dark pink and chromosome 11 is represented by the blue.
Karyotype with translocation of chromosome 9 and 11. Notice the blue on chromosome 9 that came from chromosome 11 and the dark pink on chromosome 11 that came from chromosome 9. None of the chromosome material is lost, it is just now in a new location.
When a parent has had multiple miscarriages caused by a rearrangement, there may be a chance that they passed on their chromosomal rearrangement. Most chromosomal rearrangements do not have any signs or symptoms other than difficulty becoming pregnant or experiencing multiple miscarriages. While inheriting a balanced translocation is unlikely, knowing a parent has a rearrangement prompts consideration of a karyotype for oneself.
There are other possible causes for miscarriages such as: age, antiphospholipid syndrome, uterine anomalies, thrombophilias, hormonal or metabolic disorders, infection, autoimmunity, sperm quality, and life- style issues (1). Some of these may have genetic underpinnings, but further research is still needed. A study investigating whether people with a family history of miscarriage are more likely to have a similar history concluded that family history is associated with a personal history of miscarriage. However, further studies are also needed, with a better design and focus on this specific question (3).
Ultimately, it is important to share with your healthcare providers if you have a relative who has experienced recurrent miscarriages. Some assessments could be considered, but most of the time, the workup for miscarriage is performed for the person experiencing recurrent miscarriage. Having a family history of miscarriage doesn't necessarily mean one will have the same experience.
If someone has a personal history of recurrent miscarriages, they can consult a maternal-fetal medicine specialist for evaluation and consider meeting with a genetic counselor, especially if a chromosome rearrangement has been identified. It is important to note that even with available evaluations, there are times when no cause is identified for the history of multiple miscarriages. Not having a cause can be challenging, and the prospect of getting pregnant without knowing if it may end in a miscarriage can be distressing. Counseling and therapy are also crucial considerations to address emotions and establish healthy coping strategies.
In summary, diving into family history is a practical step for those in the pregnancy planning phase or currently pregnant. If there's a background of recurrent miscarriages, particularly in your mother's history, it raises valid questions about what to expect. This discussion focused on considerations and potential causes for recurrent miscarriage. Consulting healthcare professionals, including genetic counselors, can be the next step for some individuals.
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* This blog constitutes general information about genetic testing and medical screening. This blog does not offer or provide medical advice or diagnosis, and nothing in this blog should be construed as medical advice or diagnosis. Do not rely on the information in this blog/article to make medical management decisions. Please consult with a medical professional before making those decisions. Do not delay in seeking professional medical advice if you think you have a medical concern. Do not disregard professional medical advice based on any information received in this blog.
