Mosaic embryos: hiding in plain sight


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VOLUME 116, ISSUE 1, P77


Richard T. Scott Jr., M.D., H.C.L.D./A.L.D.


Reflections on "The morphokinetic signature of mosaic embryos: evidence in support of their own genetic identity" by Martin et al.

Read the full text here. 

Fertility and Sterility

Editorial Office, American Society for Reproductive Medicine

Fertility and Sterility® is an international journal for obstetricians, gynecologists, reproductive endocrinologists, urologists, basic scientists and others who treat and investigate problems of infertility and human reproductive disorders. 


Go to the profile of Pandiyan  Natarajan
3 months ago

We are all Mosaics:

We are all mosaics if sufficient cells from sufficient tissue are examined. Some tissues exhibit greater degree of Mosaicism, others less. 

The idea of  diagnosing Mosaicism in embryos is fraught with problems from the word go. It is well known that the placenta is replete with mosaicism. The trophoblast cells go to form the placenta. Trophoblast Mosaicism does not necessarily mean the Inner cell mass is also Mosaic. Besides, the exact significance of Mosaicism in causing Fetal anomaly is unclear.   

Mosaicism is a mitosis error & may not be indicative of problems with the Inner cell mass..

We are putting the cart before the horse in starting to practice routine PGT-A before the science is well-established. PGT should be restricted only to cases where it is clearly indicated.  Routine Testing of all embryos with Invasive Trophoblast Biopsy would lead to confusion and loss of precious embryos.

In the 1990s I have personally observed triploid embryos, kept aside, (before embryoscope and PGT-A were available) progress normally to a Grade AA Embryo, clearly indicating  that there is more to Embryo than their appearance and Pre implantation Genetic Testing.

Embryos, Endometrium and Implantation continue to be enigmas and we are still unable to decipher what is a good embryo and endometrium and why embryos fail to implant.

Professor Dr Pandiyan Natarajan,

Professor and Head of the Department of Andrology and Reproductive Medicine,

 Chettinad Super Speciality Hospital,

 Chettinad Academy of Research and Education,

 Kelambakkam, Chennai,

Tamil Nadu, India- 603103