Whether Chromosomal Abnormalities Cause Risk of Miscarriage or Not?

Do Chromosomal Abnormalities Cause a Miscarriage?

Medically Reviewed By
Dr. Sabiha Anjum (Gynecologist/Obstetrician)
View more Gynecologist/Obstetrician Our Panel of Experts

A miscarriage is a painful experience for a woman. Some of the major causes of miscarriages are chromosomal abnormalities. There are chances that the chromosomes the baby inside the womb receives from the birth parents may be incorrect, leading to abnormalities in his development. While this can complicate the pregnancy and lead to improper growth in the babu, it may also lead to a miscarriage.

What Is a Chromosomal Abnormality

When the sperm fertilises an egg, a lot of chemicals are exchanged along with the connection of chromosomes, which govern how a child will grow. When these chromosomes are not present in a proper manner in the zygote, a chromosomal abnormality is said to occur. This usually is caused when the sperm cells have anomalies or the egg walls are damaged, or even as the zygote develops.

Why Chromosomal Abnormalities Cause Miscarriages

The reason for miscarriage due to a chromosomal abnormality has not been fully discovered with conclusive evidence. Nevertheless, such anomalies can cause the fertilised egg to be formed partially and not be strong enough to implant itself in the uterus. This can cause an early miscarriage. In other cases, the zygote that is formed with these abnormalities might be deemed hazardous by the internal bodily processes. These could trigger the immune system to attack the zygote and terminate the pregnancy altogether.

Risk Factors for Pregnancies Affected by Chromosomal Abnormalities

Women who have chromosomal abnormalities during one pregnancy may think that they would have it in the next pregnancy also; however, this is not true. The chances of chromosomal abnormalities recurring multiple times is a rarity since the pairing itself is quite unique in each individual. Therefore, having a miscarriage due to chromosomal abnormalities won’t necessarily mean the next one would have to suffer the same fate.

The risk of a miscarriage is more when the age of the parents is more. The pregnancy risks in women over the age of 35 increase substantially, along with the chances of chromosomal abnormalities. Similarly, men who are 40 or above may have a problem that affects the chances of their female partners conceiving, too.

Other factors such as exposure to toxic chemicals at work or in other environments could also disturb the proper combination of chromosomes. A certain combination of genes or factors involving the structuring of sperms and eggs could lead to chromosomal abnormalities, too.

Risk Factors for Pregnancies Affected by Chromosomal Abnormalities

Which Chromosomal Abnormalities Cause Miscarriage

There are two major abnormalities in chromosomes that can trigger a miscarriage.

1. An Abnormality in the Parent Chromosome

Such scenarios are rather rare and happen only in extremely unique cases when either parent tends to have an unnatural chromosome. At times, such chromosomes could switch positions and pair with other chromosomes, causing an abnormality known as translocation chromosomal anomaly. Such a case can result in a baby that is completely normal, but the chromosomal pairing or anomaly could result in a miscarriage.

2. An Abnormality in the Embryo Chromosome

This is the abnormality that is the major culprit behind a majority of cases ending with miscarriages. The most popular cause in this scenario is an unnatural number of chromosomes in the embryo, which could either be less than or more than the required 23 pairs. Such improper pairs result in an embryo that fails to develop fully and struggles to survive in the womb, leading to a miscarriage. Few babies survive through the entire term but are born with extremely debilitating birth defects and developmental disorders, which make their lives quite difficult. These chromosome abnormalities manifest as a missing pair, or a missing partner, or an extra chromosome.

Recurrent Miscarriage and Its Link With Chromosomal Abnormalities

Knowing the potential of various chromosomal abnormalities leading to miscarriage will make you wonder if this is a case that would repeat constantly. Well, the chances of this happening are substantial if the chromosomal abnormalities are due to genetic issues in the parents. Most miscarriages usually end in the initial stages with the foetuses aborting spontaneously. In other cases, chances of chromosomal pairing going wrong are quite a rarity to repeat again.

Treatment for Chromosomal Abnormalities That Cause Miscarriages

When there are chromosomal abnormalities in the embryos, there is no treatment as such that can prevent it from happening. The chances of chromosomal abnormalities increase with the age of the parents, and its possibility of occurrence can only be devised and screened, but cannot be treated. If a woman doesn’t undergo a miscarriage, the baby will be born, but he may have substantial defects.

For embryos that suffer from translocation abnormalities, opting for a different egg or a sperm could prevent it from happening to an extent. IVF is usually recommended in such cases.

How to Prevent a Miscarriage Due to Chromosomal Abnormalities

While certain genetic factors and biological conditions cannot be changed, there are a bunch of ways to prevent a miscarriage or a chromosomal abnormality. Taking care of certain lifestyle choices and staying away from toxic substances that affect the body in various ways can be a great factor in reducing the chances of chromosomal abnormalities in parents. Also, it is best to try again for another child since the chances of the same abnormality repeating are minimal.

Tests for Chromosomal Abnormalities Post Miscarriage

In order to know how to avoid a miscarriage due to chromosomal abnormalities, there are a few tests that can be undertaken to detect the root cause of the problem.

1. Parental Karyotyping

This is where the genetic pattern of the parents is examined by understanding the foetal formation. In parental karyotyping, blood from both or either of the parents is taken. Then the chromosomes are observed from the blood cells. Chromosomes from both sources are studied, and any genetic issues are determined beforehand.

2. Testing of Foetal Tissue for Abnormal Chromosomes

The success of this test usually depends on conducting it right after a woman experiences a miscarriage. The genetic makeup and chromosomal structure are studied to its inner depth using tissue of the foetus to discover any factors that resulted in its inability to stay within the womb.

Planning for Future Pregnancy After a Miscarriage

Depending on your doctor’s recommendations and the test results of your abnormality, there may be an option for you to try to conceive again if the chances of the abnormality repeating itself are minimal. However, if a recurring miscarriage seems to be a possibility, it is best to opt for a different sperm or an egg by undertaking IVF in order to have a healthy baby.

Genetic counselling will be offered to the couples who are high risk for chromosomal abnormalities, or those who already had recurrent miscarriages due to certain genetic abnormality. It is advisable that you take this counselling to know in detail what the further suitable plan for you could be.

A baby’s development in the mother’s womb is a complex process which depends on numerous factors. By getting a good idea of the genetic makeup of yourself and the foetus, you can reduce the chances of a miscarriage and ensure that you have a healthy baby.

Also Read: Recurrent Miscarriage

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