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What Is Aneuploidy?

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If you're having trouble getting pregnant, experiencing recurrent miscarriage or of advanced maternal age, you may hear the term aneuploidy in some of your discussions with the fertility doctor. But what does aneuploidy mean?

Simply put, aneuploidy means having the wrong number of chromosomes in a cell.

If you'll remember from biology class, a chromosome is an organized structure of DNA and protein that is found in cells. Typically, human cells have 23 pairs of chromosomes — 22 pairs of autosomes and one pair of sex chromosomes. But how do human cells get this total of 46?

Normally, an egg has 23 chromosomes, and a sperm has 23 chromosomes; therefore, the when the egg is fertilized, the resulting embryo has a total of 46 chromosomes – half from the mother and half from the father. However, sometimes an egg or sperm may have an abnormal number of chromosomes, which results in an embryo with aneuploidy. Embryos with aneuploidy are likely to not implant in the uterus or result in a miscarriage. The majority of first trimester miscarriages are the result of aneuploidy, and as a woman ages, she is more likely to have embryos with aneuploidy and miscarriages.

The good news is, advances in reproductive medicine such as preimplantation genetic screening may help fertility doctors choose the best embyros for transfer during in vitro fertilization; and, therefore, reduce the risk of miscarriage or failed IVF. For more information on aneuploidy, miscarriages and PGS, check out the following articles:

Chromosomal Abnormalities and Miscarriage
Miscarriage, Aneuploidy, and Preimplantation Genetic Screening

Watch as Dr. Jamie Grifo explains how PGS can help prevent miscarriage, or pregnancy loss, due to chromosome abnormality in an embryo:

To schedule a consultation with a fertility doctor, contact our Patient Care Advocates at 1-855-955-BABY (2229) or email

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