High Quality Embryo Transfer Success Rates

Embryo grading helps fertility clinics determine the best embryos to use for IVF. Learn more about high quality embryo transfer success rates here.

Embryo grading plays a role in ensuring the success of your surrogate’s embryo transfer, determining the embryo's potential to develop into a healthy pregnancy. By evaluating embryos based on their appearance, development rate and cellular structure, embryologists can select the highest quality embryos for transfer.

This selection process significantly enhances the likelihood of implantation, reducing the number of IVF cycles needed and increasing the chances of a successful pregnancy. For intended parents, a good quality embryo transfer success rate offers a clearer path to bringing home a healthy baby.

If you have high quality embryos that are ready for transfer, or you are beginning the embryo creation process, connect with us today. We can help match you with a surrogate so that you can finally become parents.

What is Embryo Grading?

Embryo grading is a process that helps fertility clinics determine the quality and viability of embryos before the embryo transfer. Medical specialists observe embryos on different days of development and look for signs that the embryos are healthy and growing.

How Important is a High Quality Embryo Success Rate?

While embryo grading is common in fertility clinics and there is some evidence that correlates higher quality embryo success rates with better pregnancy and birth rates, grading may vary from clinic to clinic, and is not the only factor in determining whether a particular embryo is likely to implant and result in a live birth.

If you have created embryos and they’ve already been graded or you are in the process, fill out our form. We can connect you with a surrogate who will begin preparing for the embryo transfer once the legal process has been completed.

Embryo Grading Days

When it comes to embryo grading, fertility clinics frequently check development on day 3, the cleavage stage and day 5, the blastocyst stage. Embryo assessment is different depending on which day the clinic grades the embryo. During the cleavage stage, embryos are evaluated based on the number and appearance of their cells. At the blastocyst stage, grading focuses on the development of the inner cell mass and the trophectoderm.

Here’s a more comprehensive breakdown of what determines a good quality embryo success rate:

Day 3 Embryos

Day 3 embryos are graded based on:

  • Cell Number: Evidence shows that when embryos have 8 cells on day three, there is a higher live birth rate, while lower numbers of cells have a lower live birth rate.
  • Cell Appearance: Cell number is fairly straightforward, but cell appearance grading is more subjective. Embryologists look for abnormal appearances, and check for equal size and shape of cells.

Day 5 Embryos

By Day 5, embryos are called blastocysts. Day five grading is more complex than day 3 grading and less consistent across fertility clinics. On day 5, fertility clinics look for:

  • Quality of ICM (Inner Cell Mass): The inner cells become the fetus, and clinics check the appearance of this area.
  • Quality of TE (trophectoderm epithelium): The cells that form the trophectoderm epithelium will develop into placenta and other tissues that are necessary for pregnancy.
  • Blastocyst Expansion: As the embryo grows, a fluid-filled cavity forms (called a blastocoel). More developed or larger blastocoels are used as markers of good quality embryos.


Why do good quality embryos fail to implant?

Good quality embryos can fail to implant for a variety of reasons, including things like:

  • Genetic abnormalities or mutations of the embryo
  • Lab environment and freezing/thawing success
  • Uterine malformations
  • Thin uterine endometrium
  • Endometrial polyps, fibroids or myomas within the uterus
  • Scar tissue within the uterus
  • Immunological alterations
  • Endometritis
  • Progesterone levels
  • Prolactin levels
  • Thyroid dysfunction

Research on embryo implantation is ongoing and not every cause is known.

What is the best grade embryo to transfer?

Embryo grading systems vary somewhat from clinic to clinic, but common grading systems usually include a letter and a number grading system (1AA-6CC). In this system, 3AA-6AA are the best grades of embryo. The number represents the stage of blastocyst development from 1-6, and the two letters note two main parts of the growing embryo (the ICM and the TE).

How likely is a 4AA embryo to implant?

4AA embryos are considered “excellent” quality embryos and have a 65% pregnancy rate.

What is the success rate of IVF with healthy embryos?

Healthy embryos have a pregnancy rate of roughly 50%-65% and a live birth rate of roughly 42%-50%.

If you already have embryos and you’re ready to start surrogacy, you can contact us here. You can also reach out and get connected to a fertility clinic if you do not have embryos.