Frozen Embryos — A Comprehensive Guide For Intended Parents Struggling to Start a Family & How Surrogacy is Key
A vital part of in-vitro fertilization and the surrogacy process is the ability to freeze embryos.
What does freezing embryos exactly entail and what is its purpose?
This article will discuss freezing embryos and the incredible role they have for surrogacy in California.
Embryos: An Overview
There may be a lot of confusion about what an embryo actually is.
While the common thinking is that every fertilized cell is a baby, scientifically, this isn’t the case.
The baby first passes through a few different phases before it is recognized as being a baby. The embryo phase is when an egg cell has just been fertilized by a sperm cell. This occurs shortly after ovulation.
A single embryo is known as a zygote. It remains an embryo, or zygote, until the 9th week of pregnancy.
By that point, the cells have formed enough to make a human baby recognizable. It transitions into the fetus phase.
In that initial 9 weeks, the cell is dividing and basically building the foundation of life. Life support networks and systems are being created. It’s during the fetus phase where growth and development of those life systems are started.
Embryos cannot be formed until an egg drops down through the fallopian tube during the ovulation cycle.
For women who suffer from infertility like tubal factor infertility, it can be impossible to become pregnant. Tubal factor infertility describes a condition in which the woman’s fallopian tube is blocked. The egg is unable to pass through the tube and into the uterus for development.
In this case, the woman would need to find a surrogate in order to have a baby.
It should also be noted that embryos form while they’re still in the fallopian tube. Sperm races up the tube and fertilizes one of the eggs inside of the ovaries. This fertilized cell then has to pass down the tube and enter the womb where it can be nourished and grown.
For women struggling with infertility, the embryo may never make it to the uterus because of tubal factor infertility or any other reason for a blockage.
In fact, you are not actually considered pregnant until the embryo has reached the uterus.
An embryo cannot grow in the fallopian tube because it doesn’t have the proper nourishment that it needs for survival. Embryos that are trapped in the tube either disintegrate themselves or have to be removed via a doctor.
Once the embryo reaches the uterus, it’s not until week five that the life systems start to be developed. Roughly, it’s the size of a pen and has three layers. The top layer is known as the ectoderm.
Eventually, this layer will form skin, eyes, the nervous system, ears, and connective tissue. The middle layer is known as the mesoderm. Eventually, this layer will see the development of the baby’s muscles, bones, kidneys, and reproductive system.
The final layer is known as the endoderm and rests on the bottom. This layer will develop into your baby’s intestines, lungs, and bladder.
Clearly, embryos are important.
So, why would you want to freeze them and what’s the difference between frozen and fresh embryos?
Frozen Embryos
The first successful pregnancy that occurred from a frozen embryo was in the 1980s.
It changed the ability to have children for couples struggling with infertility everywhere. First, it’s important to know why you might want to freeze your embryos. Many people freeze embryos because they want to become pregnant later in life.
By freezing them now when they’re young, their embryos will be at their healthiest.
Other people may decide to freeze their embryos because they want to give them to others. Some couples are unable to form an embryo together. They require embryos from another mother.
By freezing them, those embryos can be preserved and delivered to the couple facing complete infertility.
They can then have the embryo transplanted within them and grow the baby as though it was their own biological child. This is an incredible experience that wouldn’t have been possible only a few decades prior.
The process begins with a woman receiving medications that will help encourage her body for fertilization.
These medications are typically prescribed and monitored by a fertility clinic.
Once the woman is ovulating, her eggs are then removed from her body. It should be noted that not all of the eggs are removed.
Unless the woman only has a small number of eggs that her body has produced, only a small sample of eggs will be removed through the in-vitro fertilization process.
Egg extraction at a fertility clinic can be performed for two different reasons.
The first is for in-vitro fertilization into a surrogate mother or the mother herself. The second is for freezing. Continuing with the process of frozen embryos, the egg donor is then finished with her part of it. It’s the sperm donor that next contributes to making the embryo.
A sperm sample is collected from the intended father and placed in a petri dish along with the eggs.
For many couples, in-vitro fertilization may be the only way in which fertilization could happen. Blockages, small egg count, small sperm count, reduced sperm movement, unhealthy eggs, or just poor health, in general, can all be reasons of why fertilization was unable to occur naturally in the body.
After the sperm has been collected, IVF continues. The sperm cells reach the egg cells and fertilize them.
During IVF, many embryos can be formed.
Most couples do and should choose to have them frozen. Not every embryo transplant into a surrogate mother is successful. By having frozen embryos readily available, the fertility clinic can quickly implant another to keep the process going.
The Freezing Process
While freezing may seem easy, it’s actually incredibly difficult in the case of embryos. The challenge is the water that exists within the cells. When the cells freeze, the water starts to form crystals. Those crystals can eventually cause the cell to burst and die.
The method to keep this from occurring is known as cryopreservation. During this process, the water within a cell is replaced with a cryo-protectant. The embryo incubates over a series of days while the cryo-protectant continues to increase within the cell. Once enough of the water has been removed, the fertility clinic then cools the embryo.
There are two freezing methods that couples usually choose:
#1 – Slow Freezing
The embryos are placed in sealed tubes and then placed in a freezer that slowly brings down their temperature over time.
The advantages of this method are that it lowers the potential for damage that the embryo might receive. It also keeps the cell from aging.
The disadvantages are that it is a time-consuming process and the machinery that it utilizes is expensive.
For certain couples who already paying for surrogacy, this cost may not be possible for them.
#2 – Vitrification
It’s the opposite of slow freezing in that the doctor freezes the embryos extremely quickly. This is necessary to freeze the cell before the crystals can form.
The advantages of this process are that it keeps the cell healthy and increases their rate of survival when it’s time to thaw them for IVF and embryo transplant.
The disadvantage is that if the doctor is unable to freeze the cell before the crystal forms, then it can damage the embryo.
This damage can make the embryo unable to develop when placed in the fetus or have other damage that could affect how well the baby develops.
Once the embryos have been frozen, the embryos are then stored inside liquid nitrogen.
Success Rate
Understandably, intended parents may be worried about the survival rate of those embryos after they are frozen.
For women and men who already have a low count of eggs and sperm, they are only able to create so many embryos. If the embryos that are frozen do not survive the thawing process, then they might be out of luck for developing a biological child.
Luckily, the success rate of thawing embryos that are frozen is quite high.
Those women who freeze their embryos early in life can often meet with a 60% chance of a successful pregnancy from using a thawed embryo. That likelihood decreases the longer a woman waits to freeze her embryos.
As the process of freezing continues to become innovated and develop, this success rate will also likely increase.
Part of the reason that it is so successful is that it allows the clinic time to prepare the host who is going to receive the embryo.
In the case of a surrogate mother, her body can be properly medicated to reach her peak fertility. Her body will recognize the embryo and accept it.
From there, the embryo can start to develop into a healthy baby.
Another aspect that some couples may worry about is whether or not the freezing and thawing process might make their children abnormal.
For example, it may lead to certain birth defects that could injure their development both in the fetus and later in life. According to a study, babies who are born from embryos that are frozen show no higher rate of birth defects or abnormalities in their development.
One last aspect to consider is whether or not slow freezing or vitrification has a higher success rate for both survival and implantation.
According to this study, it was the process of vitrification that actually had a higher success rate. The survival rate was 96.9% over the slow freezing rate of 82.8%.
Furthermore, the implantation rate of success was 16.6% against slow freezing’s 6.8%. That’s comparative to the clinical pregnancy rate of 40.5% versus the slow freezing’s rate of 21.4%.
How Long Can Embryos Stay Frozen?
One interesting factor to consider is just how long an embryo can stay frozen for.
For those who are looking to find a surrogate and utilize a surrogacy agency in California to have their baby, you may want to know what your timetable looks like.
Technically, a frozen embryo can remain viable for virtually any time. One that is frozen correctly can last forever. In theory, at least.
So, if you are a woman who wants to concentrate on her career for some time, it isn’t a bad idea to have some of your eggs removed through IVF along with your partner’s to form an embryo that can be used for pregnancy later in life.
Even women who are experiencing menopause can still have a baby.
They would just need to use a surrogate to ensure the healthy development of their embryo after it is thawed and transplanted.
While a woman who experiences menopause may still be able to carry a baby with medication, it’s always a safer bet to find a surrogate to carry the baby instead.
Embryos are placed in sealed containers where the temperature is -321ºF.
At this temperature, it is virtually impossible for biological processes to occur. Aging, for example, is halted. Life continues but it is halted.
Because cryopreservation of embryos is still relatively new, there are no long-term studies of how long an embryo can be frozen for and successfully implanted for a full-term pregnancy.
Currently, the record stands at a 24-year-old embryo.
In that case, the embryo that was used was from another couple who donated their embryo for other mothers to use. The baby was born healthy and developed normally.
Frozen Versus Fresh Embryos
At this point, you may be wondering if having a fresh embryo is any more or less successful than having an embryo that is frozen transplanted.
In one study that compared frozen and fresh embryos, there was virtually no difference between success rates.
This means that even if you choose to freeze your embryos, you’re just as likely to have a successful embryo transplant of that embryo than you are with an embryo that was just harvested and fertilized.
That’s great news for women who want to wait a bit to have children.
In fact, one research study even suggested that freezing your embryos may be what leads to healthier babies and pregnancies in the future.
This is likely because the woman’s body is able to be prepared over a longer time period for the acceptance of the embryo. With a prepared body, the body is more likely to accept the embryo without any consequences.
The difference between frozen and fresh embryos is the duration of time in which they are transplanted into a uterus.
In the case of fresh embryos, they are transferred into a surrogate mother or intended mother only a few days after fertilization. Clinicians and doctors keep a close eye on the embryo as it develops outside of the body to ensure that is healthy and successfully dividing.
Once it has reached a certain level of development, usually around the day five or six marks, it is then placed within the body.
This is different from embryos that are frozen.
Instead of being placed back within the body a few days later, the embryos are frozen and stored. The mother is able to wait several weeks, months, or even years before they find a surrogate and have the embryo transplanted into them.
During that time, they can live their life and make preparations for including a baby into their family. They are able to ensure that they are going to be financially stable to support a baby once they decide it’s time for the embryo transfer to occur.
In the case of a surrogate mother, the fertility clinic can best prepare her body for the transfer without worrying about time constraints.
For some women, it may take longer to respond to medication than others, in which case using frozen embryos is preferable.
Both share the same procedure for embryo transfer—both frozen and fresh embryos.
The target womb, be it surrogate or intended mother, is given medications to boost their fertility and acceptance of the embryo once it has been inserted into the womb.
The only difference between the two is that with the embryos that were frozen, the surrogate is able to take medications over a longer period of time than a surrogate who only has a few days before the embryo is made and before it is transferred.
This added time can further help the surrogate’s body be ready to accept the embryo.
Who Benefits from Freezing Their Embryos?
As a family that is eager to start having a baby, you may wonder who can benefit from freezing their embryo.
Those who suffer from genetic conditions that might make pregnancy difficult can certainly benefit from freezing their embryos.
Also, most fertility clinics in California will freeze embryos before testing them for genetic abnormalities—this can be a big benefit of freezing.
Another group of people who can benefit from freezing their embryos is those who suffer from cancer. Whether it be ovarian cancer or cancer of the lung, if you are going to be undergoing chemotherapy, it can have a negative impact on your eggs.
Some of the chemotherapy treatments used can damage the eggs in your body, making fertility impossible.
If you are going to be undergoing chemotherapy, then you should freeze your embryos for future use. A surrogate can then carry a baby that you desire to have after you’ve recovered.
Finally, those who want to have children later in life can benefit from freezing their embryos.
Even women who have passed into menopause can still have a child of their own if she had her embryos frozen earlier in life. The younger you are when the embryo is recovered, the healthier the child will be.
In Summary
For intended parents who struggle with their fertility or want to have children later in life, freezing your embryos is a great solution.
It allows you time to prepare for the coming of a baby. With the use of a surrogate, you can have a healthy baby no matter how long you wait for the embryo transfer.
Both fertile and infertile couples can benefit from freezing their embryos and using a surrogate to carry the baby full-term. Fertile parents can choose to wait and focus on their careers. Infertile parents can increase the chances of having a baby of their own.
Surrogacy is the key to both.
If you’re an intended parent and you’d like to know more about any fertility clinics near you, or you’d like to use a trusted surrogacy agency in Sacramento, please fill out this form.
