In my practice, one of the most common questions I receive before embryo transfer is: how many embryos are transferred? The question is entirely natural, because many patients and many couples start from the idea that a higher number would automatically increase the chance of success. In reality, the decision is more nuanced and must be made according to prognosis, reproductive history and the safety of both the mother and the future pregnancy.
When I discuss embryo transfer, I always explain this step in the context of the entire journey of In Vitro Fertilization (IVF), because the answer to the question of how many embryos are transferred cannot be separated from the quality of the embryos obtained, the age of the patient and the real objective of treatment: a healthy singleton pregnancy with the lowest possible risk.
Why the Question “How Many Embryos Are Transferred” Does Not Have a Standard Answer
I often tell patients that there is no universally correct number for everyone. The fact that in one case a single embryo is transferred and in another case two are transferred does not mean that one of the approaches is “better” in an absolute sense. It simply means that the decision was adapted to that particular case.
In current guidelines, the trend is clear: where prognosis is good, transferring a single embryo is often preferred in order to reduce the risk of multiple pregnancy without losing sight of the total chance of achieving a live birth. ASRM recommends that the transfer of one euploid embryo be limited to one, regardless of age, and ESHRE underlines that the choice of the number of embryos should be individualized, based on clinical and non-clinical factors.
So, when we discuss how many embryos are transferred, the correct answer is not “as many as possible,” but “as many as offer the best balance between chance and safety.”
What Criteria I Use When Deciding How Many Embryos Are Transferred
Age and Reproductive Prognosis
The patient’s age remains an important criterion, but it is not the only one. In general, in patients with a good prognosis, especially when there are good-quality embryos or genetically tested embryos, I more often recommend the transfer of a single embryo. By contrast, in some situations with a more guarded prognosis, the discussion may also include the transfer of two embryos, if the risk-benefit balance justifies that choice. ASRM guidelines differentiate recommendations according to age, embryo stage and prognosis.
Embryo Quality and Developmental Stage
It is not enough to ask how many embryos are transferred without analyzing what type of embryos we have. A well-developed blastocyst cannot be directly compared with an embryo at an earlier stage, and a euploid embryo has a different prognostic value from an untested embryo. HFEA shows that, for most women, it is good practice for a single embryo to be transferred, while the other good embryos are frozen, precisely because selecting the embryo with the better potential changes the logic of the decision.
In cases where embryonic genetic selection is also relevant, I correlate the discussion with the role of screening for aneuploidy (PGT-A), because a tested, euploid embryo may support the recommendation for single embryo transfer more strongly.
History of Previous Attempts and Medical Context
Another essential aspect is the medical history. If there have been previous failed cycles, if ovarian reserve is low or if there are important uterine or obstetric factors, the decision is personalized. Even then, however, I never start from the assumption that more embryos automatically means better.
I also consider the patient’s general condition. If we are talking about a situation in which a multiple pregnancy would significantly increase maternal risk, my recommendation becomes even more clearly oriented toward the transfer of a single embryo. ASRM explicitly states that patients with associated medical conditions for whom multiple pregnancy may mean substantial morbidity should not receive more than one embryo.
Why More Embryos Do Not Automatically Mean a Better Chance
This is, in fact, the point where the greatest confusion appears. Many couples start from the intuitive idea that if we transfer two or three embryos, the chance doubles or triples. In practice, things do not work that simply.
What I aim for is not only achieving a positive pregnancy test, but achieving a well-progressing pregnancy and a healthy birth. Increasing the number of embryos transferred may increase the risk of multiple pregnancy, and multiple pregnancy comes with real risks: prematurity, low birth weight and more frequent obstetric complications. CDC shows that multiple births associated with ART involve important risks for both mother and child, and HFEA underlines that single embryo transfer is, for most women, safer and just as effective.
That is why, when I explain how many embryos are transferred, I insist on the idea that the objective is not “to put in more,” but to choose intelligently. Sometimes, two consecutive transfers of one embryo each may support a safer strategy than the simultaneous transfer of two embryos, at the cost of a higher risk of twins. Recently published data show that consecutive single embryo transfer strategies can maintain good results while at the same time reducing multiples and the associated complications.
“You deserve to be heard, seen, treated with respect, and supported throughout every stage of life.”
When the Transfer of Two Embryos May Be Considered
There are situations in which this option may be discussed. I do not exclude it in principle, but I do not use it as a rule either. It may become relevant in patients with a poorer prognosis, at more advanced reproductive ages or after previous failures, when the clinical context justifies such a choice and when the patient clearly understands the risks.
At the same time, I recommend that this decision should not be made in isolation, but in relation to the rest of the protocol. For example, sometimes the choice between fertilization methods and embryo selection indirectly influences the discussion about how many embryos are transferred, which is why it is also worth understanding the context of IVF vs ICSI and how we choose the right procedure.
After embryo transfer, I also explain realistically what follows, without absolute promises, because correct information about pregnancy after IVF reduces anxiety and helps the patient better understand the next steps.
Frequently Asked Questions
How many embryos are usually transferred in an IVF cycle?
At present, in many situations, the transfer of a single embryo is recommended, especially when prognosis is good. In certain cases, the transfer of two embryos may also be discussed, but the decision is not standard and must be individualized.
Why are two or three embryos not automatically transferred?
Because a higher number of embryos increases the risk of multiple pregnancy, and this is not a minor complication. Prematurity, low birth weight and maternal risks all increase when more than one embryo implants.
Does age influence the decision regarding how many embryos are transferred?
Yes. Age matters, but not on its own. A 39-year-old patient with certain characteristics may receive a different recommendation from another patient of the same age but with a different history and a different type of embryos available.
If I have very good embryos, is it better to transfer two?
Not necessarily. Precisely when we have very good embryos, single embryo transfer may be an excellent choice, because it maintains the chance of pregnancy while reducing the risk of twins.
Can PGT-A change the transfer recommendation?
Yes. If there is a euploid embryo, the recommendation for single embryo transfer often becomes stronger, precisely because the prognosis of that embryo is better.
After repeated failures, are more embryos automatically transferred?
Not automatically. Previous failures require a careful reassessment of the causes and the strategy, but they do not mechanically justify increasing the number of embryos transferred.
Does single embryo transfer greatly reduce the chance of success?
Not necessarily. In many situations, single embryo transfer is considered a safe and effective solution, especially when there are good-quality embryos and the possibility of freezing the others.
Who decides, in the end, how many embryos are transferred?
The decision is made medically, together with the patient or the couple, after full counseling. I consider it essential for the recommendation to be clear, well-argued and adapted to the specific case, not to fears or to the emotional pressure of the moment.
Dr. Andreas Vythoulkas’ Role in Choosing the Number of Embryos Transferred
At this stage, my role is to translate the medical data into a recommendation that is clear, balanced and honest. When I explain how many embryos are transferred, I am not aiming only for a technical decision, but also for a correct understanding of its implications. The patient needs to know why I recommend a single embryo transfer or, in certain cases, why I take two embryos into consideration.
In my practice, I always focus on the relationship between the real chance of implantation and obstetric safety. I analyze age, reproductive history, embryo quality, embryology data, any genetic testing and the general medical context. I believe that a good recommendation is one that protects both the objective of achieving pregnancy and the chance of reaching a healthy birth, with risks that are as well controlled as possible.
Talk to me about
How Many Embryos Are Transferred
Sources
- American Society for Reproductive Medicine (ASRM) – Guidance on the limits to the number of embryos to transfer
- European Society of Human Reproduction and Embryology (ESHRE) – Embryo transfer guideline
- ESHRE – Patient leaflet: Number of embryos to transfer during IVF/ICSI
- Human Fertilisation and Embryology Authority (HFEA) – Decisions to make about your embryos
- Centers for Disease Control and Prevention (CDC) – Assisted Reproductive Technology Surveillance
Similar Articles
Embryo Implantation: What Signs May Appear at the Beginning
Sonohysterography (Sono-HSG): When I Recommend It, How Much It Costs and What We Do After the Result
