Causes of Miscarriage, a Multipart Series

Part III, Random Chromosomal Errors

In life, when things don’t go as expected, the natural human reaction is to seek an explanation. When the local market is out of bread, we ask why? If your pizza comes with anchovies instead of artichokes, we inquire as to the reason.  If your luggage is lost on a business trip, we demand an explanation.  Answers such as; the delivery truck broke down, the waiter has messy handwriting or that there was a storm in Reno do not change the fact that we were disappointed, however understanding the cause helps us to deal with the disappointment.  

One of the most difficult aspects of miscarriage is accepting that there may be not be an adequate explanation for why it has happened.  Even for patients who choose to undergo every test and explore all possibilities, an answer may not be available.  In such circumstances, doctors may use a term like “bad luck” in hopes of quelling the angst.  In some ways, the lack of understanding can be almost as painful as the loss itself. 

The truth is that the majority of unexplained or “bad luck” losses do happen for a reason, usually a chromosomal error.  The chromosomes are 46 individual strands of genetic material (DNA) which reside in almost all the cells of the human body.  They provide instructions for every bodily function, from neurotransmitter regulation to hair growth. 

Each person on this earth (except identical twins) has a completely unique and individual set of chromosomes which was created at the time of fertilization.  DNA from the sperm and DNA from the egg are broken up, shuffled together and reconfigured to create a new set of DNA which has never existed before, and will never exist again.  This DNA is the blueprint of what makes you….you.  As one can imagine, the process is complex and susceptible to to mistakes.  It is these mistakes which can lead to miscarriage.

Of the more common mistakes we see include;

-         Formation of an extra chromosome, known as trisomy.

-         Deletion of a chromosome, known as monosomy.

-         Addition or deletion of part of a chromosome

-         Addition of a complete extra set of chromosomes, known as triploidy.

In truth there are many ways in which the chromosomes can be distorted, most of which will lead to lack of implantation or miscarriage.

Fortunately, the majority of these errors are random, meaning that they are not more likely to recur.  This is important and the reason that doctors use the term “bad luck” to describe them.  Bad luck implies that although something disappointing has happened, it is not more likely to happen again.  In the case or miscarriage, that is mostly true.

If you have questions about miscarriage or fertility in general, please feel free to contact us.