Clinics often recommend single embryo transfer in surrogacy because the goal is one healthy pregnancy at a time. Transferring one embryo lowers the chance of a multiple pregnancy compared with transferring more than one. It does not guarantee pregnancy, and it does not reduce the chance of twins to zero.
In a single embryo transfer surrogacy plan, safety and informed consent matter as much as the hoped-for pregnancy rate.
ASRM says single embryo transfer should be strongly recommended in gestational-carrier cycles because multiple pregnancy can create additional health risks for the person carrying and for the fetuses.
“Wouldn’t two embryos give us two chances?”
Renee and Mark had waited years to create embryos. When their gestational carrier, Alana, reached transfer planning, they wondered whether transferring two embryos would make the attempt more efficient.
Their physician reframed the question. Two embryos do not create two separate, controlled chances. Both can implant. A multiple pregnancy can mean more monitoring and a higher risk of complications. Alana’s health and informed consent were central to the plan.
The clinic recommended transferring one embryo. Renee and Mark still had to accept uncertainty. One embryo meant one transfer attempt, not one promised baby.
Connect Embryo Number to Your Surrogacy Plan
What single embryo transfer means
Single embryo transfer, often shortened to SET, means the clinic places one embryo into the uterus during that procedure. When more than one suitable embryo is available and the family chooses one, patient resources may use the term elective single embryo transfer, or eSET.
SET does not mean intended parents need only one embryo for their whole journey. A first transfer may not implant. A pregnancy may begin and then end. Another embryo may be needed for a later attempt or a future sibling plan.
SET also does not eliminate every possibility of twins. One embryo can rarely divide after transfer, leading to identical twins. The clinic can explain that remaining risk without turning it into a prediction.
Why multiple pregnancy changes the risk discussion
Twins may sound like a joyful shortcut after a long fertility journey. Medically, a twin pregnancy is not the same as two singleton pregnancies happening together.
ASRM notes that multiple gestation increases risks for the pregnant person and fetuses. Even twins have more morbidity than singletons. Possible concerns can include preterm birth, low birth weight, pregnancy-related high blood pressure, diabetes, cesarean delivery, and intensive newborn care. An obstetric clinician should explain risks in the gestational carrier’s own medical context.
In surrogacy, the decision also affects someone who is carrying a pregnancy for another family. The gestational carrier has the right to understand the proposed number of embryos, possible multiple pregnancy, prenatal testing, and the possibility of multifetal pregnancy reduction before transfer.
The intended parents’ hope for a shorter path cannot replace the carrier’s informed medical consent.
How the clinic chooses the embryo
The physician and embryology laboratory may consider several pieces of information:
- the age of the person who provided the eggs when they were retrieved;
- embryo development stage and morphology grade;
- whether PGT was performed and what the report says;
- prior IVF and transfer history;
- warming and laboratory findings; and
- the clinic’s current transfer policy.
A better grade or a euploid PGT-A result does not guarantee implantation. These details help the clinical team rank options. They do not turn the selected embryo into a certainty.
PGT-A is not a requirement for every single embryo transfer. ASRM states that the value of PGT-A as universal screening for all IVF patients has not been demonstrated. The clinic should explain why it recommends testing or not testing in your case.
Review PGT-A Questions Before Surrogacy
What should be agreed before medication begins
Renee, Mark, and Alana did not wait until transfer morning to discuss embryo number. Their medical and legal conversations happened before the cycle calendar became active.
Use this decision checklist:
- Confirm how many embryos the clinic recommends transferring.
- Ask why that recommendation fits this embryo and this carrier.
- Make sure the gestational carrier receives medical counseling directly.
- Discuss the remaining chance of identical twinning after SET.
- Review what the agreement says about embryo number and medical consent.
- Plan what happens if the transfer is canceled.
- Plan what happens if the embryo does not survive warming.
- Decide how another transfer would affect timing, cost, and the match.
- Discuss future sibling goals without using them to pressure the current transfer.
- Record who communicates the final laboratory and transfer decisions.
Questions for the clinic, laboratory, and lawyer
Ask the fertility clinic
- Why are you recommending one embryo in this case?
- Is there any medical reason you would consider more than one?
- What are the clinic’s outcomes after single versus multiple embryo transfer in comparable cases?
- How do you explain the risk of identical twins after one embryo?
- What happens medically after an unsuccessful transfer?
Ask the embryology laboratory
- How will you rank the available embryos for this transfer?
- What will you assess after warming?
- If the first embryo does not survive warming, is another embryo warmed automatically or only after new consent?
- How are grade, PGT result, and development day recorded?
Ask the reproductive-law attorneys
- Does the agreement clearly address the maximum number of embryos for a transfer?
- How does it preserve the gestational carrier’s right to make medical decisions about her body?
- What does the agreement say about a canceled cycle, an unsuccessful transfer, or another attempt?
- Are the intended parents and carrier represented by separate attorneys?
Professional roles should not blur
The fertility physician determines what is medically appropriate and obtains consent. The embryologist assesses and prepares the embryo. The gestational carrier decides whether to consent to the procedure after medical counseling. Separate attorneys explain and negotiate the agreement.
LittleBee can coordinate appointments, information, and expectations. It cannot order the transfer of one or more embryos, interpret laboratory findings, or override the carrier’s medical choices.
Follow the Frozen Embryo Transfer Timeline
Common questions
Does transferring two embryos double the chance of pregnancy?
No. Outcomes do not increase in a simple one-plus-one pattern, and both embryos may implant. Ask the clinic for case-specific information that separates pregnancy chance from multiple-pregnancy risk.
Can one transferred embryo still become twins?
Yes. A single embryo can sometimes divide. SET lowers the chance of multiples compared with transferring more than one embryo, but it cannot remove the chance completely.
Who makes the final decision about embryo number?
The decision must stay within medical standards, clinic policy, informed consent, and the legal agreement. The gestational carrier’s bodily autonomy remains central. State law and contract language vary, so both sides need independent legal advice.
Does SET mean we should create more embryos before matching?
Not automatically. Discuss embryo number, treatment history, family size goals, time, and budget with your fertility physician. Then give a potential surrogate an honest picture of what may happen after an unsuccessful transfer.
Renee and Mark did not leave with a guaranteed outcome. They left with a safer goal they could share with Alana: one carefully planned transfer, one embryo, and room for the clinic to respond to what actually happened.
Discuss Your Transfer-Planning Stage