Chromosomal Abnormalities and Pregnancy: Research Review

Although many chromosomal abnormalities are debilitating or fatal, sometimes the only indication of a parent’s chromosomal abnormality is reproductive difficulty. Abnormalities can include deletions, duplications, and genetic rearrangements where sections of chromosomes have been shuffled around.

Despite being otherwise healthy, parents with chromosomal abnormalities might have trouble producing eggs or sperm with a full set of normal chromosomes. A chromosomal analysis visually examines the parents’ chromosomes for any major structural anomalies. Because this is a visual test, it only detects large chromosomal changes containing multiple genes; it is not a genetic analysis that will detect gene-specific mutations.

Physiology

One of the most common forms of chromosomal abnormalities in healthy individuals is a translocation. This is what happens when a chromosome breaks and one or more fragments reattach to a different chromosome. In this scenario, the person usually still has all of the genes required for full health, but when their chromosomes are sorted to produce sperm or eggs, those sex cells might not be formed with a full set of the genes required for life.

Published clinical data

Chromosomal abnormalities are recognized to be a common source of infertility.

Chromosomal abnormalities have also been linked to miscarriage. In a population of 2,382 couples who had experienced two or more consecutive miscarriages, 5.4% of the couples were found to have an abnormal set of chromosomes in at least one partner. When those couples with chromosomal abnormalities were followed through their next pregnancy, they were significantly more likely to have another miscarriage compared to couples without chromosomal abnormalities.