A 3 D model of chromosomes.

Genetics and Early Pregnancy Loss

Talk to a Care Navigator

By: Dr. Sony Sierra, MD, FRCSC, REI, Deputy Medical Director and Partner

The majority of losses that happen early in pregnancy are due to random genetic error or “aneuploidy”.

This can happen when an egg that has an abnormal number of chromosomes is fertilized (meiotic error), or if there is a multiplication or division error in the number of chromosomes after fertilization (mitotic error). Both can happen due to just “bad luck”, or due to age-related changes in the spindles or the machinery in the egg that drives these important duplication and division steps.

Most often, these errors result in a negative pregnancy test but also are the most common reason for an early pregnancy loss.

How can you know if this is the reason for the loss?

The only way is to have the pregnancy tissue tested for chromosomal numeric error. This can be done by collecting the miscarriage tissue and sending it for genetic analysis designed to diagnose numeric errors called cytogenetic analysis with microarray, or next-generation sequencing.

If an error or the results confirm the pregnancy loss was “aneuploid” is confirmed, you will be reassured that this loss was unavoidable. Your TRIO physician will provide a program of supportive care, and early monitoring moving forward for trying again.

If the pregnancy loss is confirmed to be “aneuploid” and there are other reproductive concerns such as a delay to conceive, advancing maternal age, or especially if you are having a difficult time emotionally with recurrent pregnancy losses,  Pre-implantation Genetic Testing for Aneuploidy with IVF can significantly reduce the risk of further aneuploid, or genetically abnormal early losses, and in some cases, decrease the time to a successful pregnancy.

If the pregnancy tissue is analyzed and found to be normal, it is important to rule out all other treatable causes of early pregnancy loss.  Your TRIO MD can discuss and arrange all these investigations and then map out a plan of management to increase your chances for a successful pregnancy.