Do you find our website to be helpful?
Yes   No

Embryonic Mosaicism and IVF Embryo Screening

Embryonic mosaicism may be detected through IVF embryo screening, also known as preimplantation genetic screening or PGS. Before proceeding with IVF embryo screening, it is important to understand the complicated topic of embryonic mosaicism and how it is identified.

 

UNDERSTANDING EMBRYONIC MOSAICISM

Embryo screening performed on embryos created through IVF is done for the purpose of providing information about the genetic health of the embryo. This information can be used to select the healthiest, most viable embryos for transfer.

Chromosomes are units that contain the genetic material of an embryo. Embryos with the usual 23 pairs of chromosomes – 46 in total – are the most likely to result in a successful pregnancy and live birth. Embryos that have too many or too few chromosomes can result in no pregnancy, early miscarriage, or occasionally a child being born with a genetic condition such as Down Syndrome.

The risk of embryonic aneuploidy (i.e., wrong number of chromosomes) increases with maternal age.

 

EMBRYONIC MOSAICISM AND THE IVF EMBRYO SCREENING PROCESS

During the screening process, several cells are removed from the outer layer of the embryo for biopsy. In most cases, all of the cells are either normal or abnormal, and we can assume that the embryo itself is therefore chromosomally normal or abnormal. Sometimes, some of the biopsied cells appear normal, while others carry chromosomal abnormalities. This is known as embryonic mosaicism.

The challenge is in determining the percentage of abnormal cells that is indicative of mosaicism.

Since only a small number of cells are biopsied, it is possible that embryos labeled as mosaic could still develop into healthy babies. Laboratories often use different standards in determining which embryo biopsies are abnormal. A growing majority consider embryos with 20 to 80 percent abnormal cells to be mosaic.

Improved screening techniques can help increase screening accuracy. For instance, by delaying biopsy until day 5 or 6 (instead of day 3), more cells can safely be removed since extensive cell growth has taken place by that stage.

 

WHAT DOES IT ALL MEAN?

Although there are no clear guidelines, mosaic embryos that contain the largest percentage of normal cells and the lowest percentage of abnormal cells offer the best chance for pregnancy. When mosaic embryos are transferred, it may be recommended that those with less than 20 percent abnormal cells be prioritized.

Genetics counseling is advised for couples with mosaic embryos. Mosaic embryos can result in successful pregnancies, but problems with specific chromosomes do carry a greater risk of miscarriage or abnormal pregnancies.

Contact your local URA clinic in Hasbrouck Heights, Hoboken, and Wayne, NJ for more information. Your friendly URA team will be happy to provide you with more details about embryo mosaicism and provide a diagnosis.

You Might Also Enjoy...

Fertility Treatments for Gay and Lesbian Couples

With today’s reproductive technology, same-sex couples have options to achieve their dream of building their family. At University Reproductive Associates, we are proud to support all paths to parenthood and help you build a happy, healthy family.

Why is Facial Hair Growth a Symptom of PCOS?

If you have polycystic ovary syndrome (PCOS), you know it affects your periods and your fertility. But many people don’t know that it can cause facial hair growth as well. Read on to learn more about PCOS.

Managing Food While Pregnant

Now that you’re finally pregnant, you want to do everything you can to ensure optimal fetal development, a smooth delivery, and a healthy baby — and that means nutrition. Here’s what you need to know about what to eat when you’re expecting.

The Link Between Diabetes and Miscarriage

Pregnancy should be a joyful time of reflection and anticipation. But if you have diabetes, you may be concerned about how it will affect your baby. And rightly so, as it’s linked to miscarriage. Here’s what you need to know.

How Uterine Septum Can Cause Infertility

Miscarriages and infertility can be heartbreaking, but if your reproductive challenges are due to a uterine septum, there’s hope for successful treatment, full-term pregnancy, and babies. Read on to learn more.