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International Registry of Mosaic Embryo Transfers

The International Registry of Mosaic Embryo Transfers (IRMET) is a consortium of centres contributing mosaic embryo data, PGT-A results, and clinical outcome information to a central database.

What are Mosaic Embryos?

Mosaic embryos refer to embryos that exhibit genetic variations within their cells. These differences arise due to errors during cell division or other genetic processes early in embryonic development. This phenomenon can lead to a mosaic pattern where different cells carry distinct chromosomal content, resulting in a mix of euploidy and aneuploidy. In assisted reproductive technologies like in vitro fertilization (IVF), when embryos undergo multicellular biopsies for preimplantation genetic testing for aneuploidy (PGT-A), the term 'mosaic embryos' is used to describe embryos that show signs of mosaicism based on the test results.

Euploid, Aneuploid, and Mosaic embryos

Our Mission

Although mosaic embryo transfer is currently offered as an option for women who undergo IVF, several concerns remain, especially regarding clinical outcomes of mosaic embryos. We aim to increase the currently limited data surrounding mosaic embryo transfer by collecting prospective and retrospective data on mosaic embryo transfer and its prenatal and postnatal outcome. We also hope to promote the formulation of an evidence-based priority scheme for mosaic embryos in the clinic. Finally, we strive to provide guidance and networking opportunities to PGT centres.

Centres Around the World 🗺️


Alexa Young, CA

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