Surrogacy can sound mysterious from the outside, and many people quietly wonder how it actually works. So, how does a surrogate get pregnant? A doctor places an embryo created through IVF directly into her uterus, in a short procedure called an embryo transfer.
The details matter to surrogates and intended parents alike. This walk-through follows each stage, from embryo creation and testing to the medications, transfer day, pregnancy test and heartbeat scan. Success rates and next steps after a failed transfer close it out.
How Does a Surrogate Get Pregnant? The Short Answer
Through IVF and a Frozen Embryo Transfer
A surrogate gets pregnant through IVF and surrogacy working together. First, a lab creates and freezes the embryo. Later, a doctor thaws it and places it in her uterus with a thin catheter.
Before that day, she takes medications that prepare her uterine lining to accept the embryo. If the embryo implants, she is pregnant, just as in any other IVF pregnancy.
No Intercourse and No Genetic Link
Intercourse plays no part in surrogacy. The intended father and the surrogate never need to meet physically for a pregnancy to happen. Everything takes place in a medical setting.
In gestational surrogacy, the egg comes from the intended mother or a donor. As a result, the surrogate shares no DNA with the baby she carries.
Gestational vs. Traditional Surrogacy: Two Different Paths
Gestational Surrogacy
Nearly all surrogacy in the United States today is gestational. The surrogate carries an embryo created from the intended parents’ or donors’ egg and sperm.
This approach keeps the roles clear. Medically and legally, she is the carrier, while the intended parents are the baby’s parents from the start.
Traditional Surrogacy and Why It Is Rare Today
In traditional surrogacy, doctors use the surrogate’s own egg, often through insemination, so she is the baby’s biological mother. That genetic link creates emotional and legal complications.
For this reason, most agencies and clinics no longer offer it. The difference between traditional and gestational surrogacy shapes contracts, parentage and even how families talk about the journey.
How a Surrogate Gets Pregnant, Step by Step
Step 1: The Intended Parents Create Embryos
The process begins long before the surrogate takes any medication. First, the intended mother or an egg donor goes through ovarian stimulation and an egg retrieval. The lab then fertilizes the eggs with sperm.
Many intended parents complete this step before they ever choose an agency. Deciding who provides the egg in surrogacy is part of their planning, never the surrogate’s role.
Step 2: Genetic Testing and Freezing the Embryos
Embryos grow in the lab for about five to six days, until they reach the blastocyst stage. At that stage, many clinics take a few cells for PGT-A testing, which checks the chromosomes.
The lab then freezes the embryos until the intended parents match with a surrogate. Freezing gives everyone time for screening and contracts without any pressure on the embryos.
Step 3: Medical Screening for the Surrogate
Next, the surrogate visits the IVF clinic for bloodwork, infectious disease tests and an ultrasound of her uterus. This medical step follows the broader surrogate screening process, and results usually come back in about two weeks.
Clinics also review her pregnancy history during surrogate medical screening. Once the doctor clears her and both sides sign the surrogacy contract, medical preparation can begin.
Step 4: Preparing the Uterus With Medication
The surrogate then takes hormones that mimic a natural cycle. Estrogen comes first to thicken the uterine lining, followed by progesterone to make the lining ready for implantation.
This phase usually lasts about three weeks. An ultrasound checks the lining along the way. Many clinics look for a thickness of roughly 7 to 8 millimeters or more before scheduling the transfer.
Step 5: The Frozen Embryo Transfer
On transfer day, the lab thaws the embryo. Guided by ultrasound, the doctor then places it in the uterus through a thin catheter. It all takes only a few minutes.
Most surrogates stay awake and need no anesthesia. A full bladder helps the ultrasound image, and holding it is often the least comfortable part of the day.
Step 6: The Pregnancy Test
The surrogate continues her medications while waiting. About 9 to 14 days after the transfer, depending on the clinic, a blood test measures the pregnancy hormone hCG.
A second test a few days later checks that levels are rising as they should. Waiting for that pregnancy test after embryo transfer is often the most emotional stretch of the whole process.
Step 7: Heartbeat Confirmation and Moving to an OB
Around week 6 or 7 of pregnancy, an ultrasound looks for the baby’s heartbeat. That milestone confirms a viable pregnancy and often triggers the start of base compensation.
The surrogate usually stays with the fertility clinic until somewhere between 8 and 12 weeks. After that, she moves to her own OB for routine prenatal care, much like any other pregnancy.
| Stage | What happens | Typical timing |
|---|---|---|
| Embryo creation | Egg retrieval, fertilization, PGT-A testing, freezing | Before matching |
| Surrogate screening | Bloodwork, ultrasound, records review | About 2 to 4 weeks |
| Uterine preparation | Estrogen, then progesterone | About 3 weeks |
| Embryo transfer | Thawed embryo placed in the uterus | A few minutes |
| Pregnancy test | Blood test for hCG, then a repeat | About 9 to 14 days after transfer |
| Heartbeat scan | Ultrasound confirms the heartbeat | Around week 6 or 7 |
| Release to OB | Care moves from the fertility clinic | Around week 8 to 12 |
Medications a Surrogate Takes Before and After Transfer
Medication schedules differ between clinics, but most follow the same basic pattern. Some surrogates also take a short course of birth control pills first, which helps the clinic time the cycle.
| Medication | Purpose | Common forms |
|---|---|---|
| Estrogen | Builds the uterine lining | Pills, patches or injections |
| Progesterone | Prepares the lining and supports early pregnancy | Injections, vaginal suppositories or gels |
| Lupron or birth control pills | Helps the clinic control cycle timing | Injections or pills |
| Low-dose aspirin or antibiotics | Sometimes added by the clinic | Pills |
Progesterone usually continues until around 10 to 12 weeks of pregnancy, when the placenta takes over. Starting IVF medication for surrogates can feel like a lot. Most women settle into the routine within a week or two.
What Embryo Transfer Day Feels Like
The Procedure Itself
Embryo transfers to surrogate mothers feel a lot like a routine gynecological exam. Most women find the embryo transfer procedure painless, with mild cramping at most.
Intended parents can sometimes watch on the ultrasound screen or join by video. Many families remember that small flash of light on the monitor for years.
The Days After Transfer
Strict bed rest is no longer standard, and many clinics suggest a quiet day followed by light activity. Your clinic will give specific rules about exercise, baths and intimacy.
Plenty of stories circulate online about what helps or hurts implantation. Most are embryo transfer myths, and following your own doctor’s plan matters far more than any trick.
How Many Embryos Are Transferred?
Why One Embryo Is the Standard
In most surrogacy journeys today, doctors transfer a single embryo. Professional guidance limits the number of embryos to transfer to one when the embryo is tested and chromosomally normal, regardless of age.
Twins and triplets carry higher risks for both the surrogate and the babies. A single embryo transfer keeps the pregnancy as safe as possible.
The Role of Genetic Testing
Testing makes a single transfer more realistic. When the embryo has normal chromosomes, its chances per transfer are higher than an untested embryo’s.
For intended parents, this can mean fewer transfers overall. Surrogates benefit too, with fewer medication cycles and less time between matching and a confirmed pregnancy.
How Likely Is a Surrogate to Get Pregnant?
Success Rates With Tested Embryos
Success depends on the embryo, the uterus and the clinic. A large national analysis of tested frozen transfers found live birth rates of roughly 50 to 54% per transfer. Notably, that study looked at patients carrying their own pregnancies, not screened surrogates.
Surrogacy is associated with strong results, since surrogates have proven pregnancy histories and pass strict health checks. That is one reason the IVF success rate with a surrogate tends to run higher.
Factors That Affect Success
- Embryo quality and genetic testing results
- The thickness and health of the uterine lining
- Body weight, since studies link a higher BMI to lower live birth rates
- Following the medication schedule exactly
- The skill and lab quality of the fertility clinic
Weight matters more than many people expect. That research is one reason agencies set BMI requirements for surrogacy, often at 29 or below.
What Happens If the Transfer Does Not Work?
A negative test is hard news for everyone, but it does not mean the surrogate did anything wrong. Embryo factors are the most common cause, and the reasons why surrogacy sometimes fails rarely involve the woman carrying.
After a short break, often one cycle, the clinic can prepare for another transfer if embryos remain. Most surrogacy contracts plan for more than one attempt and pay the surrogate for each transfer. Seen across the whole surrogacy process, a second transfer usually adds a couple of months rather than restarting everything.
Frequently Asked Questions About How a Surrogate Gets Pregnant
Does an Embryo Transfer Hurt?
Most women describe it as uncomfortable at most, similar to a Pap smear. No anesthesia is usually needed, and you can go home shortly afterward.
How Soon After the Transfer Does Implantation Happen?
A frozen embryo at the blastocyst stage usually implants within a few days of the transfer. The blood test comes later because hCG needs time to rise to a measurable level.
Can a Surrogate Get Pregnant by Her Partner During the Process?
It is possible in theory, which is why clinics give clear instructions about intimacy and protection around the transfer. Following those instructions protects everyone involved.
Can a Surrogate Use Her Own Eggs?
Not in gestational surrogacy. Using her own egg would make her the biological mother. That is traditional surrogacy, which most agencies do not offer.
How Long Does the Whole Process Take?
From application to embryo transfer, many journeys take several months. How long surrogacy takes depends on screening, matching and legal steps. The pregnancy itself then lasts about nine months.
How Surrogacy by Faith Supports the Path to Pregnancy
Surrogacy by Faith follows ASRM guidelines and transfers only PGT-A tested embryos. That approach supports a 92% first-transfer success rate, against the 40 to 60% national average the agency cites. In practice, most of its surrogates need only one transfer.
Surrogates follow a medication protocol of about three weeks before their frozen embryo transfer. Monthly payments of about $5,000 begin after heartbeat confirmation around week 7, and a surrogate still receives $2,500 if a transfer fails.
Most team members have been surrogates themselves, with a combined 8 babies between them. They have sat through the same injections, the same waiting and the same first heartbeat scan.
Would you like to carry for a family through this process? The surrogate application takes just a few minutes. Intended parents with embryos ready can begin through the intended parent application.
Sources
ASRM, Recommendations for practices using gestational carriers (2022): https://www.asrm.org/practice-guidance/practice-committee-documents/recommendations-for-practices-using-gestational-carriers-a-committee-opinion-2022/
Live birth rates after euploid frozen embryo transfer, SART CORS analysis: https://pmc.ncbi.nlm.nih.gov/articles/PMC7822968/
Centers for Disease Control and Prevention, What Is Assisted Reproductive Technology: https://www.cdc.gov/art/whatis.html