Causes & Treatment

Q&A with Laurel Fertility Care Embryologist

Eloise Edington  |  3 Aug 2022

The success of fertility treatments like IUI, IVF and ICSI hinges on collaboration between your fertility doctors, nurses, and an expert embryology team. While you might not always see them, embryologists are hard at work behind the scenes. They maintain the lab, freeze, test, and monitor your embryos. And if you’re going through IVF, you’ll meet them during your egg retrieval procedure.

Embryologists are not MDs, but highly trained medical professionals, usually holding a master’s degree in the specialist nature of their work. They care for gametes (sperm and eggs) and embryos in vitro.

Your top embryology questions

In today’s expert Q&A, we’re speaking to San Francisco’s leading fertility clinic, Laurel Fertility Care. Always up for the knottier topics, our chat ticks off the TTC community’s most popular embryology questions, from embryo grade to genetic testing, and more.

Embryologist Devin Monahan joined the Laurel Fertility Care team in 2013. Numerous research and review papers feature Devin’s contributions, and he’s presented research at several international IVF conferences. 

We asked Devin – 

Q: Is the ICM (first letter) the most important piece of the embryo grade? 

A: All pieces of the embryo grade are important. At Laurel Fertility Care, we don’t find that the ICM grade is any more predictive of favorable IVF outcome than the trophectoderm grade when transferring good or fair quality embryos. However, we prioritize ICM grade when selecting an embryo to transfer (e.g., we would select a 4AB over a 4BA for transfer).

Q: If our embryos are abnormal, should we avoid transferring them, or a mosaic one?

A: This is an interesting and controversial topic in our field right now. I would not recommend transferring an aneuploidy embryo. I would recommend transferring a low-mosaic embryo depending on the type of mosaicism (avoid anything with chromosomes 13,18,21,X,Y). 

Although the scientific literature suggests mosaic embryos have a lower chance of implanting, they still lead to healthy live births. At LFC, we have transferred several mosaic embryos that have led to healthy pregnancies.


 Q: We’re getting abnormal results. Would testing reveal which chromosomes are missing? 

A: Yes, the genetic testing will show which chromosomes are problematic. It’s important to look because if the same chromosomes are causing the abnormality, there could be a translocation present.

Q: Do you think PGT is more important than grade? My doctor told me to ignore the grade since my embryo was PGT normal.

A: The simple answer is yes, PGT is more important, but grade still has predictive value. We find that within normal embryos, good quality ones have a higher implantation potential than fair or poor-quality embryos. Furthermore, our day 5 embryos appear to do better than day 6 embryos.

Q: If an embryo doesn’t grow past day 3, is that an egg or sperm quality problem?

A: It’s almost impossible to say why a specific embryo stops growing. There have been some studies that have looked at the chromosomal composition of arrested embryos and found increased genetic abnormalities. So arresting cell division and embryo development may be a way of abnormal embryos shutting down. These genetic abnormalities found in embryos arise from eggs much more often than sperm.

Q: Why do some clinics push embryos past day 5 to 6 or even 7?

A: We would never go past day five for a fresh transfer. But if we’re going to do an embryo biopsy, we may need to grow them longer. This is so the embryo is big enough, and there are enough cells to perform the biopsy safely. We wouldn’t want to compromise the embryo by removing some cells from a small day 5 embryo. 


Ready to talk embryology in detail? Book a Laurel Fertility Care consult, for the very best care in San Francisco, or head to one of the boutique clinic’s sister locations, in Fresno or modesto, CA. 

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