Surrogacy and Embryos: Things to Consider
When beginning a surrogacy journey, one of the most complex parts of the process often happens before pregnancy even begins—the creation and transfer of embryos. The embryo stage is where science, hope, and tough choices all meet…and it’s not always simple. Intended parents and surrogates alike may hear terms like PGT-A testing, mosaic embryos, and single or double embryo transfer and feel overwhelmed by the decisions ahead. While these topics can feel technical, they are essential in shaping the path forward. Here’s a breakdown of what each means, along with important considerations.
PGTA Testing: A Peek Inside the Embryo
Preimplantation Genetic Testing for Aneuploidy (PGTA) is a screening process performed on embryos created through IVF. It looks at the number of chromosomes in an embryo to help determine if it’s “euploid” (chromosomally normal) or “aneuploid” (abnormal). It helps doctors choose the healthiest-looking embryos for transfer.
Why it’s done: To increase the likelihood of a healthy pregnancy and reduce the chance of miscarriage.
What to know: While PGT-A can provide valuable insight, it isn’t a guarantee. Some embryos labeled as “abnormal” may still have the potential to develop into healthy pregnancies, and some that test as “normal” may not implant successfully.
For Intended Parents, it often feels like a way to protect their dream—choosing the embryo most likely to result in a healthy baby.
For Surrogates, it can bring comfort, too, knowing the embryo being transferred has been carefully “checked” and is considered to be a healthy embryo for embryo transfer.
But it’s important to remember PGTA isn’t perfect. Sometimes embryos labeled “normal” don’t implant, and sometimes embryos labeled “abnormal” surprise everyone.
Mosaic Embryos: The “In Between”
Not all embryos get a clear result. Some come back as mosaic, which means they have a mix of normal and abnormal cells. This can feel like a confusing gray area. The truth? Some mosaic embryos have gone on to become perfectly healthy babies, while others don’t implant at all.
What this means: A mosaic embryo contains a mix of normal and abnormal cells.
The big question: Can it still result in a healthy baby?
In some cases, yes—many children have been born from mosaic embryos.
However, the risks may be higher, and outcomes can be less predictable.
For intended parents, the decision to use a mosaic embryo can be emotional—balancing hope with uncertainty.
For surrogates, it’s important to know if you’re comfortable carrying a mosaic embryo and to have open conversations with the parents and your doctor.
Double Embryo Transfer: Twice the Chance, Twice the Risk
Sometimes, parents and doctors consider transferring two embryos at once especially if there are embryo quality issues and implantation failure, that is called a double embryo transfer “DET”. But there are things to think about as a surrogate:
Higher chance of multiples (twins or more), which can increase risks for both surrogate and babies (preterm birth, complications, higher medical needs).
Surrogates usually talk about this early on in their match—whether they are comfortable with a double embryo transfer (which we do not allow through our agency and most clinics do not allow either).
Most clinics encourage a single embryo transfer (SET) especially when working with a gestational carrier, simply because it’s safer.
ASRM practice guidelines in most cases recommend transferring a single embryo during an IVF cycle because it has statistically shown to lower the number of multiple gestations and lead to healthier birth outcomes
Final Thoughts
The embryo stage of a surrogacy journey can bring both excitement and uncertainty. Whether navigating the possibility of transferring an embryo that is not PGT-A tested, considering transferring a mosaic embryo, or debating how many embryos to transfer, the key is open communication between intended parents, their fertility team, and the surrogate. At the end of the day, embryos aren’t just cells in a dish—they are hope, possibility, and potential. For intended parents, they represent years of dreaming. For surrogates, they’re the beginning of a very personal, life-changing journey.
Every choice carries weight, but none have to be made alone. With the right guidance and mutual respect, intended parents and surrogates can move forward with clarity and confidence—knowing each decision is part of building the family they’ve been dreaming of. Thinking of exploring surrogacy? Reach out to our team here!
