How does Embryo Transfer Work?

During in vitro fertilization, an important stage involves transferring the fertilized embryo into the uterus for implantation.


Embryo transfer is one of the three key stages of in vitro fertilization (IVF). As one of the final stages of the process, it is a critical stage in the success of treatment. There are many different reasons women undergo IVF treatment to become pregnant, and ensuring that you are educated about every stage of the process is important for your physical and mental health throughout. Here is what you need to know about embryo transfer:


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The Stages of In-Vitro Fertilization


Embryo transfer is one of the many stages of in-vitro fertilization. IVF is an incredibly complex treatment divided into multiple exciting and important stages. While everyone experiences IVF in their own unique way, there are some benchmark stages that occur throughout the process. Three of the most identifiable stages of IVF are ovary stimulation, retrieval, and embryo transfer.

Ovary Stimulation


During ovary stimulation, a woman takes multiple hormonal medications (oral and injectable) to stimulate the ovaries to produce viable eggs. Some of these medications can cause side effects, so you will likely have many check-in appointments booked to make sure everything is moving smoothly. The goal is to encourage multiple follicles to mature into viable eggs for fertilization. 

Egg Retrieval


Once enough viable eggs have been produced, it’s time to retrieve them. In a procedure most commonly done in a doctor’s office under intravenous sedation (the good stuff to take the edge off), the eggs are surgically extracted from the ovaries. Up to 15 viable eggs can be removed during this procedure, all to be stored for later use or fertilized in a lab to prepare for embryo transfer.

How Embryo Transfer Works


Provided that the fertilization stage goes according to plan and produces one or more viable embryos, we have finally made it to the embryo transfer stage of the process. Yay!

Typically taking place 2-5 days after the successful fertilization, embryo transfer is also commonly done in a doctor’s office under a mild sedative. Similar to getting a PAP smear, a speculum is inserted into your vaginal to expose your cervix. Then, a thin and flexible catheter is inserted through your cervix and into your uterus. Using the tube as a guide, a syringe is used to insert one or more viable embryos into the uterus. If the procedure is successful, implantation typically occurs within 6-10 days. Talk about some impressive science!


Risks of Embryo Transfer


Like all medical procedures, there are some risks involved in undergoing embryo transfer. Some important risks to understand before undergoing embryo transfer include:


  • Potential damage to your reproductive system during insertion
    • While this is very rare, it is possible for damage to your vagina, cervix, or uterus to occur during insertion. To minimize this risk, it is important to ensure that your IVF provider is experienced in the procedure.


  • Potential damage to the viable embryos during insertion
    • Inserting the newly fertilized embryos is a very delicate procedure. It is possible for the embryos to be damaged during insertion, which makes successful treatment less likely.


  • The possibility of multiple embryos successfully implanting into the uterus
    • It is very common for women to opt for multiple viable embryos to be inserted during one procedure to increase the likelihood of a successful pregnancy. While it is not common, it is possible that all embryos inserted can result in a successful pregnancy. Consult with your provider about your comfort level and the safety of inserting multiple viable embryos.


  • The potential for non-successful pregnancies
    • Despite everything going right, transferring a viable embryo into the uterus does not guarantee pregnancy. The percentage of successful embryonic implantation into the uterus from this procedure is 41%, meaning that there is a significant chance that the procedure may not be successful.


Putting It All Together


Embryo transfer is an incredibly important stage of IVF – and it’s honestly an incredibly impressive scientific procedure. Every pregnancy is different, so becoming educated about all of the different ways women become pregnant is incredibly important and empowering. So, is IVF and embryo transfer right for you? If you have been experiencing infertility and are considering exploring fertility-assisting options, speak with your primary care provider about the benefit and risks of IVF and embryo transfer.