genetics
Egg Donation and Blood Types
When it comes to egg donation, you may be wondering if the blood type of the egg donor matters. While it is not necessary for the donor to have the same blood type as either parent, it’s helpful to understand how blood types work.
When it comes to egg donation, you may be wondering if the blood type of the egg donor matters. While it is not necessary for the donor to have the same blood type as either parent, it’s helpful to understand how blood types work. In this article, we’ll review the blood types, how they are inherited, and when blood type matching matters.
What are blood types?
Blood types are determined by the presence or absence of certain antigens, or proteins, on the surface of our red blood cells. Blood types include A, B, AB, and O. Blood type A has the A antigen, blood type B has the B antigen, blood type AB has both A and B antigens, and blood type O has neither A nor B antigens.
Within each blood type, there is a positive or negative (A+, A-, and so on). The positive or negative sign next to the blood groups is known as the Rhesus (Rh) factor. Rh factor is independent of blood type. It is determined by the presence or absence of a specific antigen on the surface of red blood cells. If a person has the Rh antigen, they are Rh-positive. If they do not have the Rh antigen, they are Rh-negative. Most people, about 85%, are Rh-positive.
According to the San Diego Blood Bank, the average distribution of the blood types in the United States are:
- O Positive (O +): 38%
- O Negative (O -): 7%
- A Positive (A +): 34%
- A Negative (A -): 6%
- B Positive (B +): 9%
- B Negative (B -): 2%
- AB Positive (AB +): 3%
- AB Negative (AB -): 1%
How is a child’s blood type determined in egg donation?
A baby's blood type is determined by the combination of genes inherited from the egg and sperm. Each passes on one of their two ABO alleles to the child. The combination of these alleles determines the baby's blood type. For example, if the egg donor is type A and the biological father (or sperm donor) is type B, the baby could be type A, type B, type AB, or even type O.
Unless both the egg donor and intended father have blood type O, in which case the baby would definitely be type O, you would need a blood test to determine the baby's blood type.
But remember how we said everyone also has an Rh factor, that plus or minus after the letter? A child inherits one Rh allele from the egg donor and one from the intended father. If both are Rh-positive, then the child will be RH-positive. If both are Rh-negative, then the child will be Rh-negative. If one is Rh-negative and the other is Rh-positive, then the child could be either.
Does the egg donor determine the blood type of the child?
The blood type of a child is determined by the combination of genes inherited from the egg and sperm. Each contributes one of two possible alleles (versions) for each gene that codes for the blood type. The Rh blood group system is determined by another gene on chromosome 1 that has two alleles: D and d. The D allele codes for the RhD protein, and the d allele codes for no Rh protein.
While the egg and sperm decide the genetic makeup of the child, they do not have control over the specific alleles that the child inherits. That is determined by the process of meiosis, which randomly selects which sperm or egg cell will fertilize the other.
What is Rh incompatibility?
Rh incompatibility occurs when a pregnant woman (either an intended mother or gestational carrier) who is Rh-negative carries a baby who is Rh-positive. Her immune system may recognize the baby's Rh-positive blood cells as foreign and produce antibodies against them. This can cause her immune system to attack and destroy the baby's red blood cells, leading to a condition called hemolytic disease of the newborn (HDN). HDN can cause serious complications for the baby, including anemia, jaundice, brain damage, and even death.
It’s important to know if you’re at risk for HDN. But the good news is that HDN can be prevented by administering a medication called Rh immunoglobulin (RhIg) or Rhogam to the mother or gestational carrier during pregnancy, which helps prevent her body from making antibodies against the baby's blood cells.
If you or your gestational carrier are Rh negative, consult with your doctor about choosing a donor who is Rh positive.
Is it possible for a child to have a different blood type than both of its parents?
Yup! As you can see in the chart shared above, there are many cases where a child would have a different blood type from their biological parents. For instance, if the egg donor was blood type A and the intended father was type B, the child could be blood type O.
Why would someone want an egg donor with the same blood type?
There are a couple reasons someone might want an egg donor with a specific blood type.
First, they may want to avoid rare blood types in the rare situation that the child would need a blood transfusion. Blood transfusions can only be given to individuals with compatible blood types. For example, if someone with blood type A receives a blood transfusion from someone with blood type B, their body may react negatively and cause serious health issues. Remember though, unless both the egg donor and intended father are type O (in which case the only option is for the child to be type O), there is no guarantee that a child will be the same blood type as one parent.
Second, blood type can also play a role in pregnancy and childbirth. If a mother or gestational carrier is Rh-negative and the baby is Rh-positive, the mother's body may produce antibodies that attack the baby's red blood cells, which can lead to a condition called hemolytic disease of the newborn. However, this is treatable and not a reason to pass on an egg donor.
Third, some parents may want to increase the chances of their child having (or not having) a certain blood type. There is some evidence that certain blood types are more protective against certain health conditions like heart attacks, memory loss, and cancer.
Lastly, parents who do not plan on telling their child about their donor-conceived origins may want to have a child with similar blood type. Although this is your family and you get to decide how / if to tell your story, research has shown over and over the importance of openness and honesty in telling children their conception story and telling it early.
Is it better to find an egg donor who has the same blood type as myself?
So does blood type matter? It is not necessarily "better" to find an egg donor who has the same blood type as yourself. It’s helpful to know the blood type of the donor, but blood type doesn’t need to be a reason to choose a donor, and most parents have other attributes that are more important to them.
As mentioned above, having an egg donor who is the same blood type as the intended mother or gestational carrier can help reduce the risk of Rh incompatibility between the baby and the intended mother, which can cause serious complications for the baby if not treated. However, blood type matching is not necessary for egg donation, and many successful pregnancies and healthy babies are born from egg donation despite not having a blood type match.
Ultimately, the decision of whether to find an egg donor with the same blood type as yourself should be made in consultation with a fertility doctor, who can provide more information and guidance on the risks and benefits of blood type matching in your specific situation.
Cofertility is a human-first fertility ecosystem rewriting the egg freezing and egg donation experience. Our Family by Co platform serves as a more transparent, ethical egg donor matching platform. We are obsessed with improving the family-building journey — today or in the future — and are in an endless pursuit to make these experiences more positive. Create a free account today!
Should I Do PGT Testing with Donor Eggs?
One aspect of IVF that many patients are offered is preimplantation genetic testing (PGT). But is it necessary to do PGT testing with embryos made from donor eggs? Read on to learn more.
When it comes to starting or expanding a family, many couples and individuals may turn to assisted reproductive technologies (ART) such as in vitro fertilization (IVF) to help them achieve their goal. One aspect of IVF that many patients are offered– whether using their own eggs or donor eggs – is preimplantation genetic testing (PGT). But is it necessary to do PGT testing with embryos made from donor eggs? Let’s dive in and find out.
What is PGT?
PGT is short for PGT-A, or “Preimplantation Genetic Testing for Aneuploidies,” and you may also hear it referred to as PGS (“Preimplantation Genetic Screening”) or PGD (“Preimplantation Genetic Diagnosis”) which are various forms of testing embryos.
PGT testing looks at an embryo to see if it contains the correct amount of chromosomes. Embryos with the right number of chromosomes — 46 — are considered “euploid,” and those with extra chromosomes or chromosome deletions are considered “aneuploid.” PGT is a way to screen for genetic disorders in embryos created through IVF before they are transferred to the uterus.
PGT testing and age
Here’s an annoying fact: the percentage of embryos that are euploid decreases as we get older. So not only do we have fewer eggs as we age, but the chances that any one egg turns into a healthy baby decreases too.
One study of over 15,000 embryos found that the lowest risk for embryonic aneuploidy was between ages 26 and 30, and that older age groups had the lowest chance of a genetically normal embryo.
As you can see, chromosomal abnormalities of embryos are normally due to the age of the egg (or rather, the age of the mother or egg donor at the time the egg is retrieved). Since donors are under the age of 33 and healthy, embryos made with donor eggs have a good chance of being genetically normal. So, is it still worth PGT testing donor egg embryos? That leads us to the next section…
The upside of PGT testing donor eggs
There are definitely some benefits to testing donor eggs:
- Gender selection. PGT testing allows for gender selection. Most clinics allow you to know each embryo’s gender, which can be helpful for families that have a preference.
- Rule out sperm issues. PGT testing of embryos made from donor eggs may also be suggested for couples with male infertility, especially if the sperm has shown chromosome translocations or abnormalities.
- Pick the healthiest embryos. PGT can detect genetic disorders such as cystic fibrosis, Tay-Sachs disease, and sickle cell anemia, allowing for the selection of embryos that do not carry these disorders.
The downside to PGT testing
However, a lot of fertility doctors will say it’s okay to pass on genetic testing with embryos made from donor eggs. Here’s why:
- It’s expensive.The cost of PGT can vary depending on the type of testing done and the clinic you're working with, but it can be thousands of dollars.
- Added time. It can take some testing companies weeks to give you the results. Time goes so slowly during IVF, and adding additional time can be a major downer.
- False positives or negatives. PGT can be prone to false positives or negatives, meaning an embryo that is genetically normal could be labeled as abnormal, or vice versa.
- There’s a small risk to the embryo. The biopsy process, which removes cells from each embryo to be sent for testing, has a chance of damaging the embryo. Also because the embryo must be frozen in order to do PGT testing, there’s risk in having to be thawed and unthawed.
But the biggest downside is that PGT might not even improve the chances of pregnancy for those using donor eggs! Remember that chart you saw above? If embryos are made from donor eggs, where the donor is under 35… the chances of each embryo being euploid is pretty high.
Let’s look at the data. A 2020 study looked at 1,291 donor-egg cycles across 47 IVF clinics– 262 cycles with PGT testing and 1,029 without. Live birth rates occurred:
- 53.8% of donor-egg cycles with PGT testing
- 55.8% of donor-egg cycles with without PGT testing
Yes, you read that right. The donor-egg cycles that skipped PGT actually had higher live birth rates than those who paid to have the embryos PGT tested. The researchers concluded that PGT testing in donor egg-recipient cycles does not improve the chance for live birth, nor does it decrease the risk for miscarriage. But it does increase cost and time for the patient.
Summing it up
PGT can be a useful tool for patients who are at risk for passing on a genetic disorder or have a family history of a particular condition, however it may not be that useful for those using healthy donor eggs. The financial cost, time, false positives or negatives, and risks to the embryo are all important factors to consider. This is definitely a question and conversation you want to have with your doctor who can help you make the best decision. Good luck!
Cofertility is a human-first fertility ecosystem rewriting the egg freezing and egg donation experience. Our Family by Co platform serves as a more transparent, ethical egg donor matching platform. We are obsessed with improving the family-building journey — today or in the future — and are in an endless pursuit to make these experiences more positive.
How Common is Donor Egg IVF?
We know that using donor eggs can greatly increase the chances of success for an infertile couple. But how common is egg donation? Let’s dive in.
Donor egg in vitro fertilization (IVF) is a fertility treatment in which an intended parent uses eggs from an egg donor to have a baby. In this process, the donated eggs are fertilized with sperm from an intended parent or sperm donor in a laboratory to create embryos. Those embryos are monitored by an embryologist while they grow into blastocysts. They are then frozen, genetically tested, and transferred to the uterus of the intended mother (or a gestational carrier) in the hope that it will implant and result in a pregnancy.
We know that using donor eggs can greatly increase the chances of success for an infertile couple. But how common is egg donation? Let’s dive in.
First, who uses donor eggs?
There are many reasons an intended parent would turn to donor eggs to have a baby:
- Infertility due to low ovarian reserve
- Repeated IVF failures with own eggs
- Infertility due to recurrent miscarriage
- LGBTQ+
- Genetic mutations
- People without ovaries
- Single males
- Women whose own eggs have been damaged by chemotherapy or radiation treatment
Regardless of the reason, donor eggs are a viable, and increasingly common, path to parenthood.
How common is donor egg IVF in the US?
The use of donor eggs has been increasing in recent years. While it's hard to know the exact number of egg donation cycles each year, we can get a good estimate through the Society for Assisted Reproductive Technologies (SART), which tracks data for nearly 400 US clinics annually.
In 2019 there were nearly 20,000 IVF transfers using donor eggs at SART-reporting clinics. That is up 14% from the previous five years. Of those transfers:
- 1,776 used fresh donor eggs
- 2,468 used frozen donor eggs
- 15,294 transferred thawed embryos
How common is donor egg IVF in the UK?
More than 70,000 donor conceived children have been born in the UK since 1991. The total number of babies born via egg donation in 2019 was 1,327, up 88% from 2009. Of those, 83% used a donor egg and the partner’s sperm. The remaining 17% used both donor egg and donor sperm.
How common is donor egg IVF in Australia and New Zealand?
In Australia and New Zealand, there were 3,316 IVF cycles performed using donor eggs (or embryos) in 2017 with 727 live births reported. Of those cycles, 86% used donor eggs and the partners sperm while the remaining used a donor embryo.
How common is donor egg IVF in Europe?
According to data from the European Society of Human Reproduction and Embryology (ESHRE), the number of donor egg cycles in Europe has been steadily increasing in recent years. In 2017, the most recent year for which data is available, there were a total of 28,377 donor egg cycles reported in Europe, representing about 5% of all IVF cycles performed in the region. It is worth noting that these figures do not include data from all European countries, as not all countries report their IVF data to ESHRE.
How common is donor egg IVF in Asia?
In China, egg donation is uncommon. That is because donor eggs can only be used if they are unused leftover eggs from women who underwent IVF. Data collected by The Chinese Society of Reproductive Medicine (CSRM) of 327 fertility clinics from 2013 to 2016 found 1,642 donor egg cycles in that time, a small fraction of the 12 million cycles.
The use of donor eggs globally
Unfortunately there’s no way to know exactly how many donor egg cycles there are globally.
But according to data from the International Committee for Monitoring Assisted Reproductive Technologies (ICMART), which collects data from 2,971 clinics in 79 countries, there were 161,139 egg donation transfers in 2018.
The use of donor eggs is more common in countries and regions with better access to IVF, and where legal, cultural, or religious beliefs make the use of donor eggs more acceptable. Plus, the use of donor eggs in IVF may be underreported in some countries, as not all countries require procedures to be reported to regulatory agencies.
Donor eggs can increase your chances of success
Around 53 percent of all donor egg cycles will result in at least one live birth. This percentage varies depending on the egg donor, recipient body mass index, stage of embryo at transfer, the number of oocytes retrieved, and the quality of the clinic.
At every age, the chances of birth with donor eggs is better, but those who benefit the most from donor eggs are women over 35 and those with low ovarian reserve. In fact, about one-quarter of women over 40 who succeeded with IVF did so through the use of donor eggs.
At Cofertility, the average number of mature eggs a family receives and fertilizes is 12. Some intended parents want to do two egg retrievals with the donor which is definitely possible. We also ask each of our donors whether they are open to a second cycle as part of the initial application — many report that they are!
You can see how many eggs are retrieved in the first cycle and go from there. If, for any reason, the eggs retrieved in that round do not lead to a live birth, our baby guarantee will kick in and we’ll re-match you at no additional match deposit or Cofertility coordination fee.
Donor eggs: where do I start?
If you are looking to use donor eggs to build your family, we’d love to help. Cofertility is a human-first fertility ecosystem rewriting the egg donation experience. Our Family by Co platform serves as a more transparent, ethical egg donor matching platform. We are obsessed with improving the family-building journey — today or in the future — and are in an endless pursuit to make these experiences more positive. Create a free account today!