Sperm fertilizing egg

Step in Surrogacy 2a: Create Your Embryos for Surrogacy

After you have signed up with an agency, the next step is to get your embryos to a fertility clinic in Mexico. An embryo is a tiny collection of cells at an early stage of development that begins when a fertilized egg starts to divide and multiply. These cells continue to divide and develop into a blastocyst, which consists of about 100 – 150 cells. The development of an embryo into a blastocyst takes about 5 to 6 days, and it is the blastocyst that will be transferred to a surrogate’s womb. Often, intended parents use the term “embryo” and “blastocyst” interchangeably – they might call a blastocyst “5-day embryo”, for example. In this website, I will use the term “embryo” throughout the articles.

A microscope picture of a human blastocyst
A microscope picture of a human blastocyst

There are two ways to prepare embryos for transfer into your surrogate. If you already have embryos made in your home country and are stored in your fertility clinic, you can ship your embryos to the clinic in Mexico. If you don’t have any embryos, you will have to create them in Mexico.

Creating Embryos for Surrogacy

If you don’t have embryos, you will have to create them through the process of in-vitro fertilization (IVF). This is a medical procedure in which an egg and sperm are combined outside the body, in a laboratory dish. The sperm used can be your own (if you are a male intended parent), your male partner’s, or an anonymous donor’s. The egg used can be your own (if you are a female intended parent), your female partner’s, or an anonymous donor’s. If you want to be genetically related to your child born through surrogacy, you will have to use your own sperms or eggs. Note that laws surrounding parentage and passing citizenship to your child can be complex and involves whether you have used your own sperms or eggs. Please read these guides for details: Guide to the Exit Process for Canadian Intended Parents, Guide to the Exit Process for American Intended Parents.

The Process of IVF: Overview

The process of IVF for the purpose of creating embryos will involve several major steps. We will look at the general steps, then look at each step more carefully.

  1. Sperm Collection: If you or your partner is a male and you wish to use your or your partner’s sperms, you and/or your partner will need to go to your Mexico clinic to deposit the sperms. Sperm is collected from the intended father by way of masturbation. The clinic’s doctor will analyze the sperms to see if they are suitable for embryo creation.
  2. Egg Donor or Sperm Donor Selection: If you require an egg donor or a sperm donor, you’ll start by selecting a donor from a catalog that your agency gives you. This step may take place before or after sperm collection happens (if you are doing sperm collection).
  3. Ovarian Stimulation: The egg donor or the intended mother undergoes hormonal treatment to stimulate the ovaries to develop multiple eggs to be released. This increases the chances of creating viable embryos. There will be a variation in the number and quality of eggs produced in this step.
  4. Egg Retrieval: Once the eggs are mature, they are retrieved from the ovaries in a minor surgical procedure known as follicular aspiration.
  5. Fertilization: The retrieved eggs and the prepared sperm are combined in a laboratory setting to encourage fertilization. Sometimes, a single sperm is injected directly into an egg to improve success rates; this technique is called Intracytoplasmic Sperm Injection (ICSI).
  6. Embryo Culture: After fertilization, the embryos are monitored as they begin to divide and develop. They are kept in a controlled environment to ensure optimal growth.
  7. Embryo Grading and Testing: Embryos are graded for their quality. Higher-quality embryos have a better chance of implanting onto your surrogate’s uterus when they are transferred. Also, intended parents have a choice to test the embryos using PGT-a test to check for chromosomal abnormalities.

1. Sperm Collection: Details

If you are a male intended parent, the first visit to Mexico may be when you go there to deposit your sperms. You will coordinate the time for visit with your agency. Some agencies make this process easier by providing you free airport pickup and drop-off. They might even book and pay for your hotel stay.

On the day of sperm collection, you would typically go to your clinic in Mexico. You will be ushered to a small private sperm collection room where you have access to WIFI or pornographic materials (heterosexual and homosexual, typically) to help you masturbate successfully. For some men, masturbation in a “public” place, even if it’s closed and locked, is an uncomfortable experience. My suggestion is to take your time, relax, and prepare visual or auditory “aid” ahead of time. Outside the collection room may be loud, so you may also want to prepare a noise-canceling headphone or a set of earplugs.

Usually, 2 to 3 batches of sperm collection are needed. This is because one batch may be used for sperm analysis. You may have to go to the clinic twice or three times, with 1 day in-between.

Before or after sperm collection, a hospital staff will also take your blood. Your blood sample will be analyzed for common infections such as HIV, hepatitis B and C, syphilis, and other communicable diseases.

What Your Fertility Doctors Are Looking For In Your Sperm Analysis

Your sperm analysis result should be made available relatively fast. The doctor in the Mexican fertility clinic will be looking at parameters such as motility, count, morphology, and volume. Depending on the parameters, the doctor may tell you or the agency either your sperms are suitable for IVF, your sperms will require ICSI during IVF (more about it, below), or your sperms cannot be used for IVF and a sperm donor is needed. To prevent the last possibility, you should do sperm analysis in your home country before coming to Mexico and make sure your sperm parameters are good.

Other tests on your sperms may also be performed. These tests include a DNA fragmentation test and a karyotype test. DNA fragmentation test measures the amount of DNA damage in sperm cells. High levels of DNA fragmentation (typically 20% or more) in sperm can affect the ability to fertilize an egg and develop into a healthy embryo. The karyotype test examines the chromosomes of the sperm to ensure they are normal and complete. Abnormalities in the chromosome structure or number can lead to fertility issues, miscarriages, or genetic disorders in the child.

2. Egg Donor or Sperm Donor Selection

If you are creating embryos in Mexico, the chance is that you will require either an egg donor or a sperm donor.

When do I need a sperm donor or an egg donor?

You might need an egg donor if one of the following applies to you.

  • You are a single male.
  • You are a male in a same-sex relationship.
  • You are a female but your ovaries do not produce viable eggs due to medical conditions or age-related factors.

You might need a sperm donor if

  • You are a single female.
  • You are a female in a same-sex relationship.
  • You are a male but your sperm parameters are not good enough to create health embryos or you are unable to produce sperms due to vasectomy, cancer treatment, or other medical conditions.

In rare cases, you might require both a sperm donor and an egg donor. For example, if you are a single female and if you cannot produce viable eggs, you will need both donated sperms and eggs. This “double donation” will pose a significant legal hurdles for some intended parents from countries that require the intended parents to be connected to their child for the purpose of passing citizenship to the child. One such country is the United States. If you need to use both a sperm donor and an egg donor, research the laws of your home country surrounding parentage and citizenship.

What kind of an egg donor should I select?

Selecting an egg donor is very much a personal decision. Some intended parents have specific preferences such as

  • The height of the donor
  • The weight of the donor
  • The education or occupation of the donor
  • The IQ scores of the donor
  • The ethnicity of the donor
  • The interests of the donor
  • The look of the donor
  • The hair color or eye color of the donor

There are no right or wrong answers, but understand that local egg donors in Mexico are (obviously) mostly Hispanic. There are traveling egg donors from other countries such as Europe and South America, but their availability varies and will come with a higher price tag. In most agencies, egg donors are classified based on their perceived “desirability” in the eyes of intended parents. An egg donor catalog may come with “Basic Donors”, “Premium Donors”, and “VIP Donors” (or words to that effect), with higher-end donors generally more attractive, educated more highly, and rarer (e.g. traveling egg donors). If you require an egg donor who is not a Mexican, you may have to pay an extra amount to find a traveling egg donor. A premium egg donor may cost an extra of up to $12,000 USD.

Another possibility is to use a frozen egg bank. There are egg banks in United States and Canada that sell frozen eggs from egg donors of various characteristics. The choices offered may be wider (you might even find eggs of a Harvard graduate, if that’s something you care about), but they also come with a steep cost – a batch of 6 to 8 frozen eggs from Egg Bank America ranges between $16,900 USD and $20,900 USD. In contrast, a young, healthy egg donor can produce between 10 to 20 eggs or more.

Many intended parents also choose an egg donor who has a higher chance of producing many healthy, live, mature eggs. The factors at play may be:

  • Age of the egg donor: In general, egg quality declines with age. Typical egg donors are between the ages of 21 and 35. However, the number of eggs in the woman declines with age, with that decline becoming more pronounced after mid 30s. One study found that the chance of live birth from an egg donor younger than 25 was lower than from an egg donor between 25 and 29. So, a “sweet spot” for an egg donor may be between the ages of 25 and 29.
  • Health and medical history: The egg donor’s medical history and that of her family should be examined and made available to you. This is to minimize the risk of inheritable diseases. Donors are usually screened for infectious diseases as well as genetic disorder.
  • Proven fertility: Some intended parents choose a donor who has previously donated eggs or has children of her own. This may indicate her fertility and the quality of her eggs.

What kind of a sperm donor should I select?

Like egg donors, choosing a sperm donor is a deeply personal choice. An intended parent might choose a sperm donor based on his height, weight, looks, education, occupation, colors of eyes or hair, ethnicity, or IQ scores. What’s different is that it takes significantly less effort to collect sperms than eggs. For this reason, sperms are generally available at a lower cost, and many surrogacy agencies use sperms from a sperm bank. In the United States, a vial of sperms can be as cheap as $400 USD. Frozen sperms from a sperm bank usually undergo rigorous screening such as ensuring healthy sperm parameters such as sperm motility and morphology.

3& 4. Ovarian Stimulation and Egg Retrieval

In order to retrieve eggs for the purpose of IVF, the woman donating eggs, who can be either you as an intended parent or an egg donor, has to be medically prepared for the process. This involves ovarian stimulation, which is a step where the donor receives hormone injections to encourage the ovaries to produce multiple eggs at once. This process usually lasts about 10 to 14 days and is closely monitored by fertility specialists through regular ultrasound scans and blood tests. The goal is to ensure the ovaries are responding well to the hormones without causing overstimulation, which can be harmful.

Once the eggs are mature, the next step is the egg retrieval procedure. This is typically performed under sedation or anesthesia to ensure comfort. During the procedure, a thin needle is guided through the vaginal wall and into the ovaries using ultrasound imaging. The eggs are gently suctioned out through the needle. This process is usually quick, taking about 15 to 30 minutes, and it is crucial that it is done with precision to avoid damaging the eggs or surrounding tissues.

A healthy egg donor may produce about 10 to 20 mature eggs. Some women may produce more than 20 eggs

Possible Complications and Delays

The abovementioned steps might sound straightforward and easy, but there are some complications that can develop, delaying the process or making the egg donor unsuitable for egg retrieval. These might be:

  1. Poor Response to Hormonal Stimulation: Sometimes, an egg donor might not respond as expected to the hormonal treatment used to stimulate egg production. This can result in fewer eggs being produced than anticipated, or in some cases, no eggs at all. The stimulation protocol might need to be adjusted, or in some cases, a different donor may need to be considered.
  2. Overstimulation: Ovarian hyperstimulation syndrome (OHSS) is a risk where the ovaries respond too well to the stimulation, causing discomfort and swelling. In severe cases, this can lead to serious health issues requiring postponement of the egg retrieval until the donor recovers.
  3. Health Issues: Any sudden health issues or infections in the donor can delay the process. For example, an unexpected illness that affects the donor’s overall health can make it unsafe to proceed with egg retrieval until she is well again.
  4. Unexpected Response to Medications: Side effects or adverse reactions to the medications used during the stimulation process can also delay or halt the process. In rare cases, allergies or other reactions might not be known until the treatment begins.
  5. Egg Donor Changes Her Mind: Yes, this happens, too. It’s possible that the egg donor has a second thought about donating her eggs, or she might find another clinic or agency that pays her more.

If your egg retrieval process is taking a long time, it’s important to communicate with your agency. Your agency should be transparent about what is happening in the process. Sometimes, the process with one donor may be delayed for months, and once you change the donor, eggs are successfully retrieved in just several weeks.

5 & 6. Fertilization and Embryo Culture

Once the eggs are retrieved, it’s time to make embryos. This phase, known as fertilization, can be conducted using a couple of methods, depending on specific medical recommendations made by your fertility doctor.

Conventional In Vitro Fertilization (IVF)

In conventional IVF, the retrieved eggs are placed in a culture dish with a carefully measured concentration of sperm cells. Over the course of several hours, the sperm cells swim to the eggs and attempt to penetrate the egg’s outer layer to achieve fertilization naturally. This method closely mimics the natural fertilization process and is often used when there are no significant issues with sperm quality.

Intracytoplasmic Sperm Injection (ICSI)

ICSI is a more targeted approach where a single sperm is injected directly into the cytoplasm of an egg using a fine needle. This technique is particularly beneficial in cases where sperm quality or quantity is a concern, or in previous instances where fertilization failed to occur with conventional IVF. ICSI enhances the chances of fertilization because the fertility specialist can choose the best sperm to inject into the egg. For example, if you have only 2% normal sperm morphology, the doctor can choose the sperm with near perfect morphology to inject into the egg.

Embryo Culture

After fertilization, the embryos are kept under strict laboratory conditions where temperature, humidity, and atmospheric gases are meticulously controlled to mimic the environment of the human body. Embryologists monitor the embryos to assess their quality and development over the next few days. This period is critical as it provides insight into the viability of the embryos. Embryos are cultured for about 5 to 6 days until they become blastocysts.

7. Embryo Grading and Testing

5-day and 6-day embryos, known as blastocysts, are graded according to specific criteria that help predict their viability and potential for successful implantation. The grading system typically assesses three key aspects: Degree of Expansion, Inner Cell Mass (ICM) Quality, and Trophectoderm Quality. Together, they make up an embryo grade in the form of Number-Letter-Letter (e.g. 5AB).

1) Degree of Expansion: This refers to how well the embryo has developed and expanded its cavity, known as the blastocoel. This number typically ranges from 1 to 6, with higher numbers indicating a more expanded blastocyst. The scores are:

  • 1: Early blastocyst (blastocoel less than half the volume of the embryo).
  • 2: Blastocyst (blastocoel half or more of the volume of the embryo).
  • 3: Full blastocyst (blastocoel completely fills the embryo).
  • 4: Expanded blastocyst (blastocoel larger than the embryo, thinning zona).
  • 5: Hatching blastocyst (blastocoel hatching out of the shell).
  • 6: Hatched blastocyst (blastocoel completely escaped from the shell).

For example, “5” can be considered desirable as it indicates a hatching blastocyst, suggesting that the embryo is beginning to hatch out of its protective outer shell, which is a good sign of its viability.

2) Inner Cell Mass (ICM) Quality: The ICM is the group of cells that will develop into the fetus. Embryologists look for an ICM that is compact, with many cells that are tightly packed together. It is typically graded as A (excellent), B (good), or C (fair), with A representing the highest potential for development.

3) Trophectoderm Quality: The trophectoderm is the outer layer of cells that will develop into the placenta and other supporting fetal structures. A high-quality trophectoderm has many cells that form a cohesive layer. It is also graded on a scale from A to C, where A indicates the best structure and cellular organization.

The embryo grading is a very important part of deciding whether you can use the embryos in embryo transfer process. If the embryo is poor, the chance of attaining pregnancy and live birth is low. A study by Zhao, Yu, and Zhang has found that the difference in successful pregnancy from embryos with “excellent” grade and those with “poor” grade is as much as 32%. If you use an embryo classified as “poor”, the chance of live birth is only 25%. Take a look at the chart, below, to see how embryo grading is classified and what pregnancy and live birth rate for each classification is.

Embryo grading chart and pregnancy and live birth rate
This chart shows embryo grading, their classification, and corresponding pregnancy and live birth rates.

Preimplantation Genetic Testing

After the embryos are graded, intended parents also have a choice to perform preimplantation genetic testing (PGT) on their embryos to screen for genetic disorders and chromosomal normality. PGT-A is the most common test performed for embryos created in Mexico. It is a test that screens for abnormalities in the number of chromosomes, which can cause disorders such as Down Syndrome, Turner Syndrome, and Klinefelter Syndrome. There are other types of preimplantation genetic testing as well. Common PGTs are listed, below:

  • PGT-A (Aneuploidy): Tests for the correct number of chromosomes, which can prevent conditions like Down Syndrome.
  • PGT-M (Monogenic/Single Gene Disorders): Tests for specific genetic disorders that could be passed on to the child, such as cystic fibrosis or sickle cell disease.
  • PGT-SR (Structural Rearrangements): Identifies embryos with structural rearrangements of the chromosomes that could lead to developmental issues.

Personally, I believe PGT-A is important to perform for the embryos that you’ll use. However, PGT-A has limitations and is certainly not a test that catches all possible genetic disorders.

  • False Positives and False Negatives: Like any diagnostic test, PGT-A is not foolproof and can sometimes yield false positive or false negative results. This can lead to the potential discarding of viable embryos or the selection of embryos with undetected abnormalities.
  • Mosaicism: PGT-A may not always accurately identify mosaicism, where some cells in the embryo have different genetic makeup than others. This can lead to the incorrect assessment of an embryo’s viability, as some mosaic embryos can develop into healthy babies.
  • Sample Error: The biopsy for PGT-A typically involves removing a few cells from the outer layer of the embryo at the blastocyst stage. There is a risk that these cells may not be representative of the embryo as a whole (mosaicism, as described above), leading to inaccurate results.
  • Limited Scope: PGT-A tests for chromosomal abnormalities (the number of chromosomes) but does not detect all genetic disorders. It won’t identify single-gene disorders or most structural chromosomal abnormalities unless combined with other types of genetic testing like PGT-M (for monogenic/single gene disorders) and PGT-SR (for structural rearrangements).
  • Impact on the Embryo: The process of embryo biopsy required for PGT-A carries a small risk of damaging the embryo, potentially affecting its viability for successful implantation and development.

The cost PGT-A ranges from $350 USD to $700 USD per embryo, but it may be included in your package pricing, depending on which package you have purchased.

Once you have a set of embryos that have acceptable quality to you and have passed preimplantation genetic testing, you are ready for them to be transferred to a surrogate’s uterus.

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