2 Frozen Embryo Transfer Success Rate

What to Know About 2 Embryo Transfers vs. Single Embryo

There are several key differences in success rates when transferring a single frozen embryo vs. multiple embryos. Here's what you need to know.

At this stage in your IVF journey, you’ve created your embryos and frozen them for future use.

If you’ve already attempted IVF before, your fertility specialist may have already told you about the success rate of a 2 embryo transfer vs. a 1 embryo transfer success rate. If this is your first time going through the IVF process, you will want to determine how many embryos will be transferred to your surrogate per transfer cycle.

To learn more about the about the surrogacy medical process, check out this article. If you have already created your embryos, you could be matched with a surrogate right away. Contact us online now to get connected with a trusted surrogacy specialist.

To help you get a better understanding of two frozen embryo transfer success rates vs. single embryo transfer, here’s what you need to know.


What is an Embryo Transfer in Surrogacy?

Just as with in vitro fertilization (IVF) to become pregnant, an embryo transfer is the final stage of the IVF process for surrogacy. The only difference is that the embryo is transferred to your surrogate’s uterus rather than the intended mother’s.  The embryo is created using your egg and sperm, or a donor’s. Once an embryo is created, it will then be implanted into the uterus using a catheter passed through the vagina and cervix, into the womb. 

This process typically unfolds in a consulting room near the laboratory and rarely requires anesthesia, although sedation may be used if necessary to relax both the patient and the uterine muscles. Most current practices only involve the transfer of a single embryo rather than two in order to minimize the chances of a multiple pregnancies.

Why 2 Embryo Transfer Success Rates are Lower than those of Single Transfers

One of the primary goals of single embryo transfers is to implant a single healthy pregnancy. The probability of a positive result when transferring a single embryo is typically around 60%, although the range can vary depending on the patient’s age.

Two embryo transfer success rates are nearly a quarter lower than single embryo transfer success rates. This is because the body will interact with the lower quality embryo of the two, resulting in a failed transfer. Transferring two high-quality embryos increases the chances of a multiples pregnancy but only increased the chances of pregnancy slightly, rather than doubling it.

When comparing the higher 1 embryo transfer success rates with 2 embryo transfer success rates, embryo quality and the number of transfers increases the chances of pregnancy rather than the number of embryos transferred at once.

2 Embryo Transfer Success Rates are Lower, but the Rate of Multiple Pregnancies is Higher

Although a 2 embryo transfer can also result in higher chances of a multiples pregnancy, with the odds of having twins being 38%. This type of pregnancy can also be more difficult for a woman to carry and can also increase risks to the babies.

Some common risks of carrying a multiples pregnancy include:

  • Low birth weight baby (weighing between 3-5.5 pounds)

  • Preterm birth (born before 37 weeks)

  • The risk of pre-eclampsia

  • Prolonged hospitalization

  • Intellectual disability

  • Cerebral palsy

  • Twin-twin transfusion syndrome (TTTS)

If a fertility doctor transfers more than one embryo but only one develops into a baby, this can still increase the risk of the baby being born prematurely and/or having a low birth weight. Although some may think that transferring two embryos guarantees twins, that isn’t always the case.  In most cases, it can lead to higher costs in addition to health risks.

Why Professionals Discourage 2 Frozen Embryo Transfers

Although it may seem beneficial to transfer more than one embryo, there are often higher risks involved. Double embryo transfers can result in a multiples pregnancy, making it difficult for a woman to carry. It can also result in higher risks to the baby.

When you begin the surrogacy process, it’ll also be harder to find a surrogate willing to transfer more than one embryo. This can further delay your journey to parenthood and can result in longer wait times.

Benefits of a Single Embryo Transfer (SET)

While two embryo transfer success rates are almost the same as a single embryo transfer, the risks are significantly less. The two key benefits of a SET are that it can result in a safe, healthy pregnancy and baby. If you’re considering using IVF to help grow your family, it’s recommended to opt for a single embryo transfer to have one baby at a time for both the safety of the mother and the child.

A woman’s overall health is one of the main considerations when determining how many embryos to transfer. If you’re unsure how many embryos you want to transfer, weigh the pros and cons, pay attention to your intuition and consult with your fertility doctor before making a decision.

If you have embryos created and are ready to move forward in the surrogacy process, reach out to us now to begin your journey to parenthood.