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Top 5 Embryology Questions (Answered by an Expert)

April 25th, 2022 | 6 min. read

By Sierra Dehmler

The world of embryology is both fascinating and mind-boggling, leaving many fertility patients with lots of questions. In this blog, we celebrate the important, life-changing work our embryologists do each day to make amazing things like IVF and cryopreservation possible, and answer your top five embryology questions!

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Wait...what's an embryologist?

Within the fertility treatment process, embryologists are the people that care for the egg, the sperm, and ultimately, the embryo. They meticulously analyze and watch over the future of someone’s family. As Erica Paganetti puts it, "embryologists are your child’s first babysitter!”

Erica Paganetti is Illume Fertility’s Senior Embryologist and Embryology Lab Manager. Along with her dedicated team, Erica fosters the early development of embryos, including the monitoring, grading, testing, and freezing. 

During the freezing process, also known as cryopreservation, an embryologist is responsible for making sure your embryos, oocytes, or sperm are all carefully stored for as long as you need.

The field of embryology is full of incredibly complex processes, which can make it seem a bit mysterious. What are embryologists doing in those dark IVF labs? Is freezing my embryos for years and years really safe? 

Below, Erica answers the top five frequently asked questions that she and her team get, particularly concerning cryopreservation and a patient’s embryo(s).

embryologists in lab

Inside the Embryology Lab at Illume Fertility

1. My embryo was abnormal…why did you still freeze it?

Embryos are cultured in our laboratory for a maximum of 7 days. Following the biopsy procedure, embryos must be cryopreserved while we wait for results from the genetics lab.

So, the short answer is, we don’t know for sure if the embryos are abnormal or not when we first freeze them, and have to wait for the genetic testing results to find out. 

Cryopreservation allows us to suspend the development of the embryos until the patient is ready to use them. The samples collected from each embryo are loaded individually, labeled, and shipped to a genetic testing facility for processing.

Genetic testing results have a turnaround time of about two weeks. So we go ahead and freeze the embryos in hopes of a normal test result.

Want to learn more about preimplantation genetic testing (PGT)?

Read our Genetic Testing Guide

2. How do you grade embryos? What do embryo grades mean?

Before we send embryo samples out for genetic testing and cryopreserve any embryos, we analyze each one using a very complex grading process. The grade is an overall assessment of the embryo’s developmental stage and quality.

There can be significant variation in embryo grading, even within a single patient’s group of embryos. We utilize the grade as an indicator of embryo quality, aiding us in selection for procedures such as embryo transfer, cryopreservation, and/or biopsy.

Embryos eligible for these procedures fall within a range of grading criteria specific to our lab. Although there is a range of grades within embryos that can be transferred, cryopreserved, or biopsied, all of these embryos have significant reproductive potential.

3. How long does it take for samples from another facility to be transferred?

When a patient comes to us from another facility, with oocytes, sperm, and/or embryos in storage, they often request the transfer-in of these specimens. We must collect all records related to these samples which include analysis reports, culture information, cryopreservation/warming protocols, infectious disease testing, and more.

Once we receive all the required paperwork, those records are reviewed for approval, and the transport can be scheduled. From start to finish, this process generally takes about 3-6 weeks.

embryology lab 2

IVF procedures taking place in the Embryology Lab at Illume Fertility

4. How long do frozen embryos last?

Cryopreservation suspends (or halts) embryo development indefinitely. These embryos do not have an expiration date and can be used at any point in the future. The world record for the “oldest” embryo used resulting in a successful pregnancy was frozen for 27 years before being thawed and transferred! How incredible is that?!

Molly Gibson, born in 2020, is the result of a cryopreserved embryo that was initially stored in 1992. Her parents have had two successful embryo transfers, both Molly and her older sister Emma (who held the previous world record for oldest embryo used in a transfer). Read more about their amazing family here

The Gibson's story is proof that cryopreserved embryos can be successfully utilized for many, many years - longer than some even imagined. 

5. If you used frozen sperm for my IUI/IVF procedure, why am I still receiving a storage bill?

Cryopreserved semen samples are generally processed and stored in multiple vials for future use. Even if you have multiple vials available for use, when thawing vials of sperm for IUI and/or IVF, vials are warmed and processed one at a time. Additional vials are only thawed when absolutely necessary.

This usually results in additional samples remaining in storage, so please be aware that fees will usually still apply, even after your cycle is complete. Ask your Care Team if you have any questions about your specific storage plan.

Did you learn something new?

We hope so! A big thank you to our Senior Embryologist and Lab Manager Erica Paganetti for answering these important questions and providing a peek inside the incredible world of embryology. 

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More IVF Resources

Want to learn more about IVF and what to expect from the fertility treatment process? We've got you covered. Explore the following articles, videos and other resources to get empowered for the road ahead.


Sierra Dehmler

Sierra Dehmler is Illume Fertility’s Content Marketing Manager - and also a fertility patient herself. Combining empathy gained on her personal journey with her professional experience in marketing and content creation, she aims to empower and support other fertility patients by demystifying the fertility treatment process.