Although most couples are blissfully unacquainted with the statistics surrounding miscarriage, pregnancy loss is in fact quite common, with 10-25% of recognized pregnancies ending in miscarriage. If you have suffered a pregnancy loss or are currently in the process of having a miscarriage, you could be wondering what caused the loss and worry about whether it will happen again. This article aims to answer the following questions:

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

There are many different reasons 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 because of a mis-division of the chromosomes in the egg or sperm involved in a conception. Typically, humans have 46 chromosomes that come in 23 pairs (22 pairs numbered from 1 to 22 and then the sex chromosomes, X and Y). For a child to develop normally it is crucial that it have the right amount of chromosome material; missing or extra material at the time of conception or in an embryo or fetus could 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 caused by chromosome abnormalities. infant loss This number may be closer to 75% or more for women aged 35 years and over who have experienced recurrent pregnancy loss. Overall, the rate of chromosome abnormalities and the rate of miscarriage both increase with maternal age, with a steep increase in women older than 35.

Pregnancy Loss – How Common is it?

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 opportunity of experiencing a miscarriage also increases as a mother gets older.

Most women who experience a miscarriage go on to possess 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 several miscarriages.

Of note, the rate of miscarriage appears to be increasing. One reason for this may be awareness – more women know they are having a miscarriage because home pregnancy tests have improved early pregnancy detection rates in the last decade, whereas in past times the miscarriage would have were just an unusual period. Another reason may 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 you can do on the DNA in a cell. For miscarriage tissue, also known as products of conception (POC), the most useful type of test to execute is really a chromosome analysis. A chromosome analysis (also known as 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 caused by 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 for example 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”. Because of this requirement, tissue that is passed at home is often unable to be tested with this particular method. About 20% or more of miscarriage samples fail to grow and thus no results are available. Additionally, karyotyping struggles 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 correct result for the fetus or it may be maternal cell contamination (MCC) where the result actually originates from testing the mother’s cells present in the pregnancy tissue rather than the fetal cells. MCC appears to occur in about 30% or 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; both most common forms of microarray testing are array CGH (comparative genomic hybridization) and chromosome SNP (single-nucleotide polymorphism) microarray. Microarray testing is also in a position to test all 23 pairs of chromosomes for aneuploidy, but does not require cell culture. Therefore, you are more likely to receive results and the results are typically returned faster when microarray testing is used. Additionally, some laboratories are collecting an example 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 can it help?

In case a chromosome abnormality is identified, the type of abnormality found can be assessed to help answer the question: “Will this happen to me again?”. Usually, 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 chance of an underlying genetic or chromosome problem in your loved ones that predisposes one to have miscarriages.

Furthermore, if a chromosome abnormality is identified it can prevent the need for other, sometimes quite costly, studies your physician might consider to investigate the reason for the miscarriage.

Lastly, knowing the reason for a pregnancy loss might help a couple of start the emotional healing up process, moving at night question of “Why did this eventually me?”.

Chromosome testing can be especially important for patients with repeated miscarriages, as it could either give clues to an underlying chromosomal cause for the miscarriages or rule out chromosome errors as the reason behind the miscarriages and invite 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 likelihood of having an effective healthy pregnancy.