Although most couples are blissfully unaware of the statistics surrounding miscarriage, pregnancy loss is actually quite common, with 10-25% of recognized pregnancies ending in miscarriage. For those who have suffered a pregnancy loss or are currently in the process of experiencing a miscarriage, you could be wondering what caused losing and worry about whether it’ll happen again. This article aims to answer the next questions:

What causes miscarriage?
How common is pregnancy loss?
What sort of genetic testing can be acquired for miscarriage tissue?
How can chromosome testing help?
Causes of Miscarriage

There are many different explanations why miscarriage occurs, but the most common cause for first trimester miscarriage is really a chromosome abnormality. Chromosome abnormalities – extra or missing whole chromosomes, also known as “aneuploidy” – occur due to a mis-division of the chromosomes in the egg or sperm involved in a conception. Typically, humans have 46 chromosomes which come in 23 pairs (22 pairs numbered from 1 to 22 and the sex chromosomes, X and Y). For a child to develop normally it is crucial that it have exactly the right amount of chromosome material; missing or extra material during conception or within an embryo or fetus can cause a woman to either not become pregnant, miscarry, or have a child with a chromosome syndrome such as for example Down syndrome.

Over 50% of all first trimester miscarriages are due to chromosome abnormalities. This number could be closer to 75% or more for women aged 35 years and over who’ve experienced recurrent pregnancy loss. Overall, the rate of chromosome abnormalities and the rate of miscarriage both increase with maternal age, with a steep upsurge in women older than 35.

Pregnancy Loss – How Common could it be?

Miscarriage is a lot more common than a lot of people think. Up to one in every four recognized pregnancies is lost in first trimester miscarriage. The chance of having a miscarriage also increases as a mother ages.

Most women who experience a miscarriage continue to have a healthy pregnancy and never miscarry again. However, some women appear to be more prone to miscarriage than others. About five percent of fertile couples will experience two or more miscarriages.

Of note, the rate of miscarriage appears to be increasing. One reason for this may be awareness – more women know they’re having a miscarriage because home pregnancy tests have improved early pregnancy detection rates over the past decade, whereas before the miscarriage would have appeared to be just a unique period. Another reason could be that more women are conceiving at older ages.

Types of Genetic Testing Ideal for Miscarriages

Genetic testing actually refers to many different types of testing that can be done on the DNA in a cell. For miscarriage tissue, also called products of conception (POC), the most useful type of test to execute is a chromosome analysis. A chromosome analysis (also called chromosome testing) can examine all 23 pairs of chromosomes for the current presence of extra or missing chromosome material (aneuploidy). Because so many miscarriages are due to aneuploidy, chromosome analysis on the miscarriage tissue could identify the reason behind the pregnancy loss.

The most common approach to chromosome analysis is named karyotyping. Newer methods include advanced technologies such as microarrays.

Karyotyping analyzes all 23 pairs of chromosome but requires cells from the miscarriage tissue to first be grown in the laboratory, a process called “cell culture”. For this reason requirement, tissue that’s passed at home is frequently unable to be tested with this method. About 20% or more of miscarriage samples neglect to grow and thus no email address details are available. Additionally, karyotyping is unable to tell the difference between cells from the mother (maternal cells) and cells from the fetus. If a normal female result is found, it may be the right result for the fetus or it may be maternal cell contamination (MCC) where the result actually originates from testing the mother’s cells within the pregnancy tissue rather than the fetal cells. MCC appears to occur in about 30% or even more of the samples tested by traditional karyotype. Results from karyotyping usually take a few weeks to months to come back from the laboratory.

Microarray testing is a new kind of genetic testing done on miscarriage samples; the two most common types of microarray testing are array CGH (comparative genomic hybridization) and chromosome SNP (single-nucleotide polymorphism) microarray. Microarray testing can be in a position to test all 23 pairs of chromosomes for aneuploidy, but will not require cell culture. Therefore, you are more likely to receive results and the outcomes are typically returned faster when microarray testing is used. Additionally, some laboratories are collecting a sample of the mother’s blood at the same time the miscarriage tissue is delivered to enable immediate detection of maternal cell contamination (MCC).

Chromosome Testing – How do it help?

If a chromosome abnormality is identified, the kind of abnormality found can be assessed to help answer fully the question: “Will this happen to me again?”. More often than not, chromosome abnormalities in an embryo or fetus are not inherited and have a low possiblity to occur in future pregnancies. Sometimes, a specific chromosome finding in a miscarriage alerts your physician to do further studies to investigate the possibility of an underlying genetic or chromosome problem in your loved ones that predisposes one to have miscarriages.

Furthermore, in case a chromosome abnormality is identified it can prevent the dependence on other, sometimes quite costly, studies your doctor might consider to investigate the cause of the miscarriage.

Lastly, knowing the reason for a pregnancy loss might help a couple start the emotional healing process, moving past the question of “Why did this happen to me?”.

pregnancy Chromosome testing could be especially very important to patients with repeated miscarriages, as it can either give clues to an underlying chromosomal cause for the miscarriages or rule out chromosome errors as the reason for the miscarriages and allow their doctor to pursue other styles of testing. For couples with multiple miscarriages determined to truly have a chromosomal cause, in vitro fertilization (IVF) with preimplantation genetic diagnosis (PGD) testing might be able to help increase their chances of having a successful healthy pregnancy.