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Embryo Grading

The following is a guide on how our IVF lab assesses blastocyst embryos utilizing the  grading scale created by Dr. David K. Gardner.

Once fertilized, embryos will continue to develop in our laboratory for up to seven days. The embryo grading process assesses embryo quality and requires a vast amount of training and skill. Our embryologists use their experience to grade the embryos in order to select the best embryo for transfer, hopefully increasing the odds of a successful pregnancy.

A blastocyst is the most advanced stage an embryo can achieve in culture and typically occurs 5 – 7 days post fertilization. Only the best quality embryos develop to the blastocyst stage. A blastocyst has two distinct cell types and a central cavity filled with fluid:

Number Describing Overall Expansion of the Fluid Cavity

Initially blastocysts are given a numerical score from 1 to 6 based upon their degree of expansion and hatching status. This part of the assessment can be performed on a dissection microscope.

1 – Early Blastocyst

Blastocoel < half the volume of the embryo

2 – Blastocyst

Blastocoel > half the volume of the embryo

3 – Full Blastocyst

Blastocoel completely fills the embryo

4 – Expanded Blastocyst

Blastocoel volume is now larger than that of the early embryo and the zona is thinning

5 – Hatching

Embryo has breached the zona pellucida and is hatching out of its shell

6 – Hatched

Embryo is completely hatched

Letter Grade for Inner Cell Mass

The second step in scoring the blastocysts should be performed on an inverted microscope. The development of the inner cell mass (ICM) can then be assessed. The ICM is given a letter, the highest score being an A.

Letter Grade for Trophectoderm

The third step in scoring the blastocysts should be performed on an inverted microscope. The development of the trophectoderm can then be assessed. The trophecoderm is given a letter, the highest score being an A.

Additional Embryo Assessment Tools


Embryo grading is much more than the embryos’ isolated appearance. It also includes their morphokinetic development as witnessed via the EmbryoScope®.

Learn more about the EmbryoScope®

Preimplantation Genetic Testing For Aneuploidies (PGT-A, Formerly Known As PGS)

The chromosomal status of an embryo can be determined with preimplantation genetic screening which evaluates all 46 chromosomes within a few cells carefully removed from each embryo. Preimplantation genetic testing for aneuploidies (PGT-A, formerly known as PGS) provides information regarding the chromosomal health of the embryo.

Learn more about Preimplantation Genetic Testing For Aneuploidies (PGT-A)

About Our Laboratory

Our laboratory team leads the way through research and innovation contributing to nationally recognized success rates.

Laboratory Research

RAD is committed to advancing the science and practice of reproductive medicine through education and research.

Embryo Grading

RAD uses the grading scale created by Dr. David K. Gardner to assess blastocyst embryos.


Time-lapse video allows our IVF experts to analyze individual embryo growth.


Preimplantation Genetic Testing for Aneuploidies (PGT-A) is a tool used to optimize the efficiency of IVF, increasing the likelihood of a successful pregnancy.


Preimplantation Genetic Testing for Monogenic/Single Gene Defects (PGT-M) and (PGT-SR) are tests that help evaluate embryos for genetic risk factors.

Semen Analysis

A semen analysis is performed in order to assess the viability of sperm before treatment at RADfertility.

RADdad At-Home Sperm Collection Kit

Our RADdad at-home sperm collection kit provides a convenient and discreet alternative to the fertility center setting.

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"We had a wonderful experience working with RADfertility. Our doctor was so sweet, informative and helpful with all of our questions. The front desk, it’s always nice to be greeted by a friendly smiling face."



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"Thanks to RADfertility, we have the most perfect addition to our family. The help and support the whole staff gave us was indescribable. We never once lost hope because of them. We will be forever grateful to each and every person we worked with during our journey."



"Dr. Neithardt was amazing. She explained in great detail all the options we had and put us at ease about the entire process. Everyone has been amazing and I have absolutely no complaints. Today I am 17 weeks pregnant and we only have Dr. Neithardt and her wonderful team at RAD to thank."

Michelle H.


"They are the most amazing team of doctors and care coordinators. After having started at another facility I was so happy to come to RAD. They are truly amazing, never make you feel like just a number and have empathy and compassion every step of the way. They also get the job done! Thanks RAD!"

Anonymous On FertilityIQ


"Dr. McGuirk is a very holistic doctor. She doesn’t just treat the fertility issues. She also points out personal health ideas (juicing, whole 30) to help heal/treat the whole patient. She is honest and open. Be open minded and trust in her process. This is a marathon, not a sprint! Dr. McGuirk will be with you the whole way."

Teresa P.


"I will never be able to put into words how thankful we are for RAD. Rhonda was there every step of the way as we were going through the process. Everyone was so welcoming and patient as we asked questions. We were blessed with a daughter, who is now three. I have already recommended and will continue to recommend RAD to people who need help growing their family!"

Newark Office

4735 Ogletown-Stanton Road
Medical Arts Pavilion 2
Suite 3217
Newark, DE 19713

Wilmington Office

Silverside Medical Center
2700 Silverside Road, Suite 2A
Wilmington, DE 19810

Dover Office

Eden Hill Medical Center
200 Banning Street, Suite 240
Dover, DE 19904

Phone: (302) 602-8822

Fax: (302) 602-8832

©RADfertility 2020