Surrogacy 101: Medical Process, Fertilization, and Transfer

For many Intended Parents and Surrogates alike, the medical side of surrogacy can feel mysterious and intimidating at first. But while the process involves advanced science, it’s also highly organized, safe, and supportive. Understanding what to expect—step by step—can help ease any nervousness and allow all parties to feel confident, informed, and ready for the incredible journey ahead.

This blog is your comprehensive, compassionate guide to the medical process of surrogacy—from fertilization and embryo transfer, to monitoring early pregnancy, and the vital role surrogates play throughout.

The Medical Process: A Team Effort

At the heart of every successful surrogacy is a collaborative medical journey, shared between doctors, Intended Parents, the Gestational Carrier (Surrogate), and fertility specialists. This process is carefully coordinated through a fertility clinic—typically chosen by the Intended Parents—with the health and safety of the Surrogate and baby always the top priority.

Each step is guided by data, experience, and care. From initial screenings to embryo transfer and follow-up monitoring, everything is done with precision, timing, and plenty of support along the way.

1. Initial Medical Screening

Before a Surrogate can move forward with a match and embryo transfer, she must undergo a comprehensive medical evaluation. This is one of the most important parts of the process and ensures she is physically ready and medically approved for pregnancy.

What’s Included?

• A full review of medical history and prior pregnancies
• Physical exam and gynecological evaluation
• Blood tests to check hormone levels, infectious diseases, and general health
• Uterine evaluation, often including an ultrasound or hysteroscopy
• Psychological screening (already completed earlier in the surrogacy journey)

If everything checks out—and most experienced surrogates have smooth evaluations—the fertility doctor will provide clearance to proceed.

2. Synchronizing Cycles: Preparing the Surrogate’s Body

Once legal contracts are finalized and a timeline is set, the Surrogate begins the medical protocol to prepare her body for embryo transfer. This is done by controlling her cycle with the help of hormone medications, which essentially mimic the body’s natural preparation for pregnancy.

Common Medications Include:

• Birth control pills (to regulate cycle timing)
• Lupron (to suppress natural ovulation)
• Estrogen (to build up the uterine lining)
• Progesterone (to support embryo implantation)

These medications are taken in carefully scheduled doses, often as pills, patches, or injections. While the idea of injections may sound daunting, clinics and agencies offer excellent support and guidance—and many Surrogates report that the shots quickly become routine.

The goal of this phase is to create an ideal uterine environment: thick, receptive lining that’s ready to welcome an embryo.

3. Creating the Embryos

While the Surrogate’s body is being prepared, the Intended Parents—or egg/sperm donors—begin their part of the journey: creating embryos through IVF (in vitro fertilization).

The Steps:

1. Egg Retrieval
   The egg provider (often the Intended Mother or an egg donor) undergoes a process of controlled ovarian stimulation with fertility drugs to mature multiple eggs. Once ready, a quick outpatient procedure retrieves the eggs.
2. Sperm Collection
   Sperm from the Intended Father or donor is collected the same day or previously frozen.
3. Fertilization in the Lab
   The eggs and sperm are combined in a lab to create embryos. This process is monitored closely for quality and development.
4. Embryo Culturing
   Embryos are typically observed for 3 to 5 days. By Day 5, many clinics prefer to transfer a “blastocyst” stage embryo, as it has a higher success rate.
5. Genetic Testing (Optional)
   Some Intended Parents choose PGT-A or PGT-M testing to screen for genetic conditions or to select the healthiest embryos. This step is optional but common in modern surrogacy.

4. Embryo Transfer Day: A Beautiful Milestone

When the embryo(s) are ready and the Surrogate’s uterus is perfectly prepared, it’s time for the big day: embryo transfer.

The Procedure:

• The embryo is placed in a special syringe with a thin, flexible catheter.
• The Surrogate lies comfortably on a table as the doctor gently inserts the catheter through the cervix and into the uterus.
• With or without ultrasound guidance, the embryo is precisely placed at the optimal spot.
• The procedure is painless and typically takes 10–15 minutes.
• The Surrogate then rests briefly at the clinic—some clinics recommend a few hours of bedrest, others advise light activity.

Doctors usually transfer only one embryo, or occasionally two, to minimize the risk of multiples. Remaining embryos are frozen for future use if needed.

It’s an emotional and hopeful moment—many Intended Parents are present or watching via video, and Surrogates often describe it as one of the most special parts of the journey.

5. The Two-Week Wait and HCG Testing

Following embryo transfer comes the hardest part emotionally for many people: the “two-week wait.” This is the window between transfer and the first pregnancy test. Even though implantation can happen within a few days, testing too early can lead to inaccurate results.

How Pregnancy Is Confirmed:

• First Blood Test (Quantitative HCG): About 10–14 days after transfer, a blood test checks for levels of human chorionic gonadotropin (HCG), the hormone that signals pregnancy. A level above 50 typically indicates pregnancy. A level over 200 may suggest twins.
• Second Blood Test: Conducted 48 hours later to ensure the HCG levels are rising appropriately (they should roughly double every 48–72 hours).

If results are positive and rising steadily—congratulations! You’re officially pregnant.

If the test is negative, all medications are stopped, and the Surrogate will usually get her period within a few days. If frozen embryos are available, another cycle can be scheduled with renewed hope.

6. Early Pregnancy Monitoring

Once pregnancy is confirmed by HCG, the fertility clinic continues to monitor the Surrogate with great care during the first 8–12 weeks.

Typical Follow-up Includes:

• Ultrasound at 6–7 Weeks: To check for a fetal heartbeat
• Repeat Ultrasounds: At 9–10 and possibly 12 weeks to ensure proper growth
• Hormone Level Checks: Continued bloodwork to verify stable estrogen and progesterone levels

As the placenta gradually takes over hormone production, the Surrogate is weaned off medications, usually by the end of the first trimester.

7. Graduation to OB Care

Around the 10–12 week mark, when the pregnancy is stable and progressing well, the Surrogate “graduates” from the fertility clinic and begins routine care with her local obstetrician.

At this point, the pregnancy becomes just like any other:

• Regular OB visits every 4 weeks, then more frequently as the due date approaches
• Standard prenatal screenings and ultrasounds
• Continued support from the agency, Intended Parents, and surrogate support networks

From here, the medical focus shifts from fertility to nurturing a healthy, full-term pregnancy.

What Surrogates Can Expect Physically and Emotionally

The embryo transfer process may sound technical, but it’s also filled with emotion, support, and incredible meaning. Surrogates often report feeling deeply connected to the Intended Parents’ hopes, while also experiencing personal joy and empowerment.

Physical Side Effects May Include:

• Bloating or mood shifts from hormone medications
• Mild cramping after transfer
• Spotting or fatigue in early pregnancy

Most side effects are mild and temporary, and surrogates are never left alone—clinics and agencies are quick to respond to any concerns.

Emotional Support Is Key

Surrogacy is beautiful, but it’s not without emotional ups and downs—especially during the two-week wait or when facing the unexpected. That’s why most agencies, including Simple Surrogacy, provide:

• 24/7 medical and emotional support
• A dedicated Case Manager
• Surrogate peer communities and counseling resources

Everyone involved wants the Surrogate to feel heard, honored, and empowered—because she is.

Why the U.S. and Canada Are the Safest Options

It’s important to emphasize that this carefully regulated, well-supported medical process is a hallmark of surrogacy in countries like the United States and Canada. Unlike programs in less regulated regions, where medical oversight may be inconsistent, and legal protections minimal, Intended Parents and Surrogates in North America can expect:

• Accredited fertility clinics with world-class technology
• Transparent legal frameworks and enforceable contracts
• Routine informed consent and health screenings
• High standards of prenatal care
• Emotional and physical support for the Surrogate

This structure ensures the process is ethical, safe, and centered on the well-being of everyone involved—especially the child.

Conclusion: Science Meets Heart

Surrogacy is one of the most powerful expressions of human cooperation, love, and technology. The medical steps—while detailed and methodical—serve a deeply emotional goal: helping create a family.

By understanding the medical side of the process, Intended Parents and Surrogates can enter this journey informed, confident, and connected. The embryo transfer isn’t just a scientific procedure—it’s a moment of hope, commitment, and compassion.

At Simple Surrogacy, we’re honored to walk alongside you every step of the way—from first injections to the final heartbeat check—and to support you through one of the most meaningful journeys life has to offer.