During an embryo transfer to a surrogate, a fertility specialist places an embryo into the surrogate’s uterus using a thin, flexible catheter. The procedure is usually brief, does not normally require anaesthesia and is often guided by ultrasound.
The embryo has already been created through IVF using an egg and sperm from intended parents, donors or a combination of both. The gestational surrogate does not provide the egg. Her role is to receive the embryo and, if it implants, carry the pregnancy.
Although the transfer itself may take only a few minutes, it follows weeks or months of screening, consent, legal preparation, embryo creation and preparation of the uterine lining. Afterwards, everyone waits until the clinic-specified date for a pregnancy test.
Embryo transfer at a glance
- The clinic confirms that the surrogate’s uterine lining and hormone timing are suitable.
- The laboratory prepares the selected fresh or thawed embryo.
- The surrogate attends the clinic, sometimes with instructions to have a comfortably full bladder.
- A clinician passes a thin catheter through the cervix into the uterus.
- The embryo is released in a small amount of fluid.
- The embryologist checks that the catheter is clear.
- The surrogate usually rests briefly before leaving.
- Prescribed medication continues until the clinic says otherwise.
- A pregnancy test is performed on the date supplied by the clinic.
Protocols differ, so the surrogate should follow her own clinic’s instructions even when they differ from a general guide.
What is an embryo transfer?
Embryo transfer is the stage of IVF in which an embryo is placed into the uterus with the aim of achieving pregnancy. It does not involve surgery or an incision.
A soft catheter is passed through the vagina and cervix. The embryo is carried within a tiny volume of culture fluid and released into the uterine cavity. The embryo is microscopic and cannot be seen with the naked eye. On an ultrasound screen, people may see a small flash from the fluid or air bubbles rather than the embryo itself.
The transfer does not implant the embryo manually. Implantation is a biological process that may occur during the following days if the embryo continues to develop and attaches to the uterine lining.
Why embryo transfer is used in gestational surrogacy
Gestational surrogacy separates the egg provider from the person carrying the pregnancy. Eggs are fertilised in a laboratory, and a resulting embryo is transferred to the surrogate.
The embryo may have been created using:
- An intended mother’s egg and intended father’s sperm
- An intended mother’s egg and donor sperm
- A donor egg and intended father’s sperm
- A donor egg and donor sperm
- A donated embryo
Because the gestational surrogate’s egg is not used, she does not contribute inherited DNA. Our guide Does a Surrogate Mother Use Her Own Egg? explains the distinction.
What happens before the transfer cycle?
Before treatment, the surrogate normally completes medical screening, infectious-disease testing and an assessment of her pregnancy history. Clinics may evaluate the uterus through ultrasound or another procedure and review medication, general health and previous births.
Intended parents and any egg or sperm donors also complete appropriate screening and written consent. Independent legal advice and counselling should be completed before treatment, particularly because parentage and surrogacy law vary by location.
The clinic then creates a calendar coordinating the embryo and surrogate’s uterine lining. A transfer should not proceed until required consents are in place and everyone understands how embryos may be used and stored.
How the surrogate’s uterus is prepared
The endometrium is the lining inside the uterus where an embryo may implant. The clinic times transfer for a period when this lining is receptive.
In a medicated cycle, the surrogate may take oestrogen to develop the lining and progesterone to create the correct implantation window. Medication may be provided as tablets, patches, injections, vaginal preparations or a combination.
In a natural or modified natural cycle, the clinic monitors the surrogate’s own ovulation and times transfer accordingly. Medication may still be used to trigger ovulation or support the luteal phase.
Ultrasound scans and sometimes blood tests help the clinic assess lining development and hormone timing. If the lining or hormone pattern is unsuitable, the clinic may postpone or cancel the cycle rather than proceed at the wrong time.
How the embryo is selected
Embryologists monitor embryos as they develop. Depending on the treatment plan, an embryo may be transferred a few days after fertilisation or at the blastocyst stage. A frozen embryo is carefully thawed before transfer.
The laboratory assesses factors such as developmental stage and appearance. If preimplantation genetic testing has been performed, those results may also inform selection, but testing does not guarantee implantation or a healthy baby.
Clinics usually recommend transferring one embryo where appropriate because transferring more than one increases the chance of twins or higher-order multiple pregnancy. Multiple pregnancy carries additional risks for the surrogate and babies.
Fresh transfer vs frozen embryo transfer
A fresh transfer uses an embryo within the same treatment cycle in which eggs were collected and fertilised. The surrogate’s medication and the egg provider’s treatment must be carefully coordinated.
A frozen embryo transfer uses an embryo that was previously frozen and is thawed before the appointment. This allows the embryo-creation cycle and surrogate’s preparation cycle to occur at different times.
Many surrogacy journeys use frozen embryos because it provides time for screening, testing and legal preparation before transfer. The best approach depends on the embryos, clinic protocol and individual medical circumstances.
What happens on embryo-transfer day?
The clinic confirms identification, consent and the embryo scheduled for transfer. The surrogate may be asked to arrive with a comfortably full bladder because this can improve the ultrasound view and help position the uterus. Not every clinic uses the same technique.
She changes as directed and lies on an examination bed. A speculum is placed in the vagina, similar to a cervical-screening examination, so the clinician can see the cervix. The cervix may be gently cleaned.
The clinician guides a thin transfer catheter through the cervical opening into the uterus. Abdominal ultrasound is often used to see its position. The embryologist loads the embryo into a smaller catheter or transfer tube, which is passed through the guide catheter.
The embryo and a small amount of fluid are released into the uterine cavity. The catheter is withdrawn and returned to the embryologist, who checks it under a microscope to confirm that the embryo is no longer inside. If an embryo remains in the catheter, the clinic can repeat the transfer step.
How long does the procedure take?
The actual transfer is often completed within several minutes, although preparation, identity checks, ultrasound positioning and post-procedure rest make the clinic visit longer.
A straightforward appointment may take around 20 to 30 minutes overall, but this varies. A curved cervix, previous cervical treatment or difficulty passing the catheter can make the procedure take longer.
It is sensible to keep the day relatively flexible rather than planning around an exact finish time.
Is embryo transfer painful?
Most people describe embryo transfer as painless or mildly uncomfortable. Sensations may include pressure from the speculum, cramping as the catheter passes the cervix or discomfort from a full bladder.
Anaesthesia is not normally needed. A person with a condition that could make the procedure painful or a history of difficult cervical access should tell the clinic beforehand so an individual plan can be made.
Severe pain is not something the surrogate should simply tolerate. She should tell the clinical team immediately if she is very uncomfortable.
Can intended parents attend the transfer?
Some clinics allow one intended parent or support person into the transfer room, while others restrict attendance because of space, privacy, laboratory rules or local policy.
The surrogate should decide who she feels comfortable having present. Everyone can discuss this before the appointment so that the day does not create unexpected pressure.
If intended parents cannot attend, the group may agree on a phone call, photograph or message, provided the clinic and surrogate consent. Medical staff should never be recorded without permission.
What happens immediately after transfer?
The surrogate may rest for a short period before using the bathroom, dressing and leaving the clinic. The embryo cannot fall out when she stands, walks, coughs or urinates; it was placed inside the uterus, not the vagina.
Some clinics recommend a quiet remainder of the day, but prolonged bed rest has not been shown to improve the chance of pregnancy. Normal gentle daily activity is commonly permitted unless the clinic gives different medical advice.
The surrogate should receive written instructions covering medication, exercise, sex, bathing, travel, work, testing and whom to call with concerns.
Medication after the transfer
Progesterone is commonly continued after transfer to support the uterine lining. Oestrogen or other medication may also continue in a programmed cycle.
The surrogate should take every dose as prescribed and should not stop because of spotting, cramping, a home test result or absence of symptoms. The clinic will say when medication can be reduced or stopped.
If a dose is missed, taken late or lost through vomiting, contact the clinic for advice rather than doubling medication without instructions.
The wait for a pregnancy test
The period between transfer and testing is often called the two-week wait, although the exact interval may be shorter or longer depending on embryo age and clinic protocol.
Clinics use a blood test for human chorionic gonadotropin or specify a home urine test date. Testing too early can produce a false negative because hormone levels are still low. A recent hCG trigger injection can sometimes contribute to a false positive if testing is premature.
A positive test shows that implantation has produced detectable hCG, but it does not confirm that the pregnancy will continue normally. Clinics may repeat blood tests and later arrange an ultrasound.
Symptoms after embryo transfer
A surrogate may experience no symptoms at all and still become pregnant. Others notice mild cramping, bloating, tiredness, breast tenderness or light spotting.
These sensations cannot reliably show whether transfer succeeded. Progesterone and other medication can cause symptoms that resemble early pregnancy, while successful implantation may cause no noticeable change.
Frequent symptom checking and repeated early tests can increase anxiety without providing dependable answers. Following the clinic’s planned test date gives a clearer result.
When to contact the clinic urgently
The surrogate should use the emergency instructions provided by her clinic. Prompt assessment may be needed for:
- Severe or worsening abdominal or pelvic pain
- Heavy bleeding
- Fainting, marked dizziness or weakness
- Chest pain or difficulty breathing
- Fever or signs of infection
- Persistent vomiting or inability to keep fluids down
- One-sided pain or shoulder-tip pain, which can be associated with ectopic pregnancy
Mild cramping or spotting may occur, but only a healthcare professional can assess symptoms in the context of the surrogate’s treatment.
What if the transfer does not work?
An unsuccessful transfer does not mean anyone caused the outcome. Even a good-quality embryo may not implant, and an early pregnancy may stop developing.
The clinic may review embryo development, transfer details, medication timing and relevant medical information before recommending another attempt. If frozen embryos remain, a later frozen transfer may be possible without repeating egg retrieval.
Intended parents and the surrogate may need time and emotional support. They should agree in advance how many attempts are contemplated, who pays additional costs and when everyone will reconsider the plan.
What happens after a positive test?
The clinic may repeat hCG testing to assess the pattern of change. An ultrasound is usually scheduled later to confirm that the pregnancy is in the uterus and assess development and heartbeat at the appropriate stage.
Medication may continue for several weeks according to clinic instructions. Care then transitions to the surrogate’s obstetrician, midwife or maternity service.
Intended parents and the surrogate should revisit communication expectations, appointment attendance, privacy, expenses and emergency decision-making as the pregnancy progresses.
Questions to ask the fertility clinic
- Will this be a fresh or frozen embryo transfer?
- Which medication will the surrogate take and for how long?
- How will the uterine lining and hormone timing be monitored?
- How many embryos does the clinic recommend transferring?
- Should the surrogate arrive with a full bladder?
- Can an intended parent or support person attend?
- Which activities or travel should be avoided afterwards?
- When should the pregnancy test be taken?
- Which symptoms require urgent contact?
- What is the plan if the transfer is unsuccessful?
Written answers help everyone follow the same plan and reduce confusion during an emotional stage of the journey.
Finding a surrogate and professional support
Intended parents can find surrogate mothers on SurrogateFinder, while potential surrogates can browse intended-parent profiles.
After a possible match, participants still need independent verification, medical screening, counselling and legal advice. A qualified fertility clinic must manage embryo creation, medication and transfer.
You can also review fertility-clinic listings as part of your research. Confirm licensing, treatment policies, costs and experience directly with the clinic.
Frequently asked questions
Is the surrogate awake during embryo transfer?
Usually, yes. Routine embryo transfer generally does not require anaesthesia, although individual circumstances may lead to a different plan.
Can the embryo fall out after transfer?
No. Standing, walking, coughing or using the toilet does not make the embryo fall out. It is placed inside the uterus.
Does a surrogate need bed rest afterwards?
Prolonged bed rest is not normally necessary and has not been shown to improve success. The surrogate should follow her clinic’s activity instructions.
How many embryos are transferred?
Often one. Transferring more than one increases the chance of multiple pregnancy and its associated risks. The clinic recommends a number based on medical circumstances and applicable rules.
When can the surrogate take a pregnancy test?
On the date provided by the clinic, commonly around one to two weeks after transfer. Testing early can give misleading results.
Can the surrogate feel the embryo implant?
There is no reliable sensation that proves implantation. Mild cramping or spotting can have several causes, and many successful pregnancies begin without symptoms.
Is the embryo genetically related to the surrogate?
Not in gestational surrogacy. The embryo’s inherited DNA comes from the egg and sperm providers.
Can a transfer be cancelled?
Yes. A clinic may postpone or cancel if the uterine lining, hormone timing, embryo condition, health or consent requirements are not suitable.
Take the next step
Embryo transfer is a short clinical procedure, but it represents the meeting point of careful laboratory work, preparation and planning. Knowing what to expect helps the surrogate and intended parents approach the day with realistic expectations.
To begin exploring potential matches, create your free SurrogateFinder profile and communicate through the platform’s private messaging system.
This article provides general information and is not medical or legal advice. Treatment protocols and surrogacy laws differ by clinic and location. Follow the instructions of your qualified healthcare team and obtain independent legal advice.