Fresh vs. frozen embryo transfer success rates


There has been a lot of debate surrounding the successes of frozen and fresh embryo transfers, and the benefits that surround these options. Many fertility specialists and treatment providers indicate that frozen embryo transfers provide a higher pregnancy success rate than using fresh embryos during assisted reproductive technology.

However, success rates aren't the only determining factor. Depending on your situation, going fresh over frozen for your embryo transfer may better suit your needs. Let’s explore what to consider when selecting between fresh and frozen embryo transfers during your IVF journey.

The difference between frozen and fresh embryo transfers

Frozen and fresh embryo transfers alike begin with ovulation induction and monitoring. When the uterus is ready, the woman will undergo an egg retrieval in which the reproductive endocrinologist will fertilize your eggs with your partner's or sperm donor's sperm.

Once the eggs and sperm have been retrieved and fertilized, a fresh embryo transfer will occur three to five days after the egg retrieval by transferring the fertilized embryo back into her uterus. 

On the other hand, a frozen embryo transfer (FET) can occur years after a woman's egg retrieval and fertilization with sperm. During a FET, your fertility doctor will implant a thawed embryo into the woman's uterus for a hopeful conception.

Success rates for fresh and frozen embryo of transfers

Many fertility clinics and the CDC have seen higher success rates when using frozen embryos rather than fresh embryos during the embryo transfer. Here’s what we’ve found:

  • A study published in 2018 by the New England Journal of Medicine, found that women with infertility issues associated with polycystic ovary syndrome (PCOS) had higher live birth rates with frozen embryo transfer. 
  • The British Medical Journal also released a study this year. They found no higher ongoing pregnancy or live birth rates in women using FET, based on them having regular periods and through gonadotropin-releasing hormones.
  • A study also found that when high-quality and healthy embryos are used on older women during embryo transfers there is no adverse effect on implantation or live birth rates, a contrasting finding to what is previously noted.

Understanding embryo transfer success rates

Both FET and fresh have multiple factors to consider when it comes to their respective success rates. Factors to consider when deciding between freezing your embryos or pursuing a fresh transfer include your age or donors' age during embryo freezing, the quality of sperm used for fertilization and your overall health during both types of transfers. 

Here’s what research conducted in 2019 shows for fresh and frozen embryo transfer success rates:

  • Higher quality embryos are associated with a 79% live birth rate with good quality at 64%. 
  • Poor quality embryos, however, are associated with a low birth rate of 28%.
  • If you decide to have your embryos frozen or take part in a fresh embryo transfer below the age of 35, your chances of higher quality embryos increase.
  • However, if you choose to freeze your embryos or take part in a fresh transfer above the age of 35, the chances of low-quality embryos increase.

So the reality is, regardless of fresh or frozen embryo transfer, your age will play a significant role in creating high to good quality embryos. Now that we’ve uncovered the success rates, it’s time to take a deep dive into the benefits of FET compared to fresh transfers.  

Five benefits of frozen embryo transfers during IVF

Success rates between the two transfer types aren't the only thing to consider when deciding which approach is better for your IVF journey. If you're choosing between the two without looking at the success rates, below are what you can expect.

Frozen embryo transfers are less costly.

IVF can be costly. If your first cycle doesn’t play out the way you expected it to, having a batch of extra frozen embryos to use will mitigate the need to go through another round of fertility medications—which can be costly. 

Preserve your fertility and plan for pregnancy when you're ready.

They say you’re never truly ready or prepared to have kids. But with frozen embryos, you and your doctor can plan when you’d like to have the transfer, allowing you to become pregnant when you're ready. If you're above 35 (or wish to get pregnant later than 35), you can preserve your fertility by freezing your eggs or embryos. This ensures that you have a healthy, high-quality set of embryos to transfer when you're ready, and not a moment too soon. 

In rare cases, intended parents who may experience infertility due to other medical conditions (such as the need for chemotherapy) choose to freeze embryos ahead of time. By fertilizing and freezing eggs and sperm before undergoing chemotherapy or other intensive medical treatment, men and women can still achieve their dreams of parenthood with conventional IVF. 

Less mental and physical stress on the woman's body.

Fresh transfers require egg development, stimulation medication and embryo growth. With FET, you won’t need to go through another egg retrieval procedure as you already have a batch of embryo’s ready for use. The only medication you’ll need to consider are those that help thicken the lining of your uterus in preparation for your embryo transfer.

Frozen embryo transfers mimic a natural cycle.

Because a fresh embryo transfer happens three to five days after the egg retrieval, the intended mother may still have significantly elevated estrogen levels. This can negatively affect implantation, increasing the risk of multiple embryo transfer procedures and putting additional stress on the intended parents. 

Gender selection and genetic testing through PGD/PGS/PGT-A.

Freezing the embryos allows your fertility specialists to perform PGD/PGS/PGT-A to check for embryo abnormalities and select the sex of your transferred embryos before transfer.

These screenings allow your fertility doctor to select the embryo(s) with the highest chance of successful implantation and pregnancy, increasing your rate of success and lowering your chances of a miscarriage. Frozen transfers are also necessary if you choose to test for single-gene disorders.

Regardless of what you consider and what you read worldwide, the best advice you can get on which transfer would be better suited to you is from a trusted fertility center with experts within this field. 

Ask your fertility clinic about their fresh and frozen embryo transfer success rates 

At Pacific Fertility Center Los Angeles, you’ll be in the hands of fertility experts who have been involved in this industry for over 30 years. For more information or advice on which transfer would be better suited to your needs, feel free to contact us. We’re always happy to help. 

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Note: This is not intended to be a substitute for professional medical advice, diagnosis or treatment. Information provided is for general educational purposes only and is subject to change without notice. Speak to your doctor directly with any questions you may have regarding a medical condition. Any information contained herein does not replace any care plan as determined by a physician. 

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