In this blog, we explore the topic of epigenetics and donor eggs – explaining what exactly epigenetics is, how it works, and the implications it has for women using donor eggs to conceive. Most importantly, we are excited to share this wealth of information as it provides a scientific explanation to solidify what we already know to be true – mothers via egg donation and their babies share a unique and special bond.
'Epigenetics' refers to changes in gene expression that are transmissible from parent to offspring that do not involve a change in the DNA sequence but have a profound impact on controlling gene expression. (1) Although the gene sequence itself cannot be altered, other environmental factors in the birth mother’s body modify the gene expression, or what the gene does.
Essentially, scientific studies of epigenetics are revealing that the activity levels of some genes may be turned down (“dimmed”) or turned up in response to other external cues from the environment - even in the womb! This means that women who conceive using donor eggs may influence the way their child's genes are expressed.
So, what is the scientific explanation for this "epigenetic effect" in the womb? It takes place through MicroRNAs, which are short sections of RNA, a chemical relative of DNA. These microRNAs are secreted in the mother's womb and act as a communication system between the mother and the growing fetus and are responsible for fine-tuning the activity levels of genes during development. MicroRNAs send biological and chemical signals to regulate how much functional activity a gene will be putting out. MicroRNAs have the potential to influence complex networks of gene activity; ranging from things such as growth and development to immunity.
It's no secret that when faced with the decision to use donor eggs during IVF, one of the biggest emotional hurdles to overcome is the realization that the child will not share genetic information with the birth mother. (The term 'birth mother' is used to refer to any woman who has given birth to a child, including mothers who are recipients of donor eggs or donor embryos.) However, epigenetics shows us that there is a scientific connection between birth mother and baby that goes beyond DNA.
Thanks to the amazing advancements in the field of epigenetics, we now know that the birth mother, even when using donor eggs, plays a significant role in the way the baby’s genes develop and contributes tremendously to the development of the baby.
Although certain characteristics of the baby may be genetically inherited from the egg donor, male partner, or sperm donor, the baby is still growing from the birth mother’s body! After the implantation of the embryo and throughout the entire pregnancy, every cell in the baby’s body is influenced by the birth mother’s body. They work together. All the nutrients that the mother is taking in are helping to build the little human inside of them; the baby starts absorbing nutrients secreted from the endometrium (the tissue lining the uterus) from the earliest stages of pregnancy onwards.
The baby lives in the birth mother’s embryonic fluid for nine months, shares her blood flow, and even knows her voice and the rhythm of her heartbeat. But beyond all these beautiful connections, epigenetics shows us that the prenatal environment provided by the birth mother may even influence the way the baby's genes are expressed.
As shared by Victoria Nino, a DEIVF mother,
"Through Biology, I gave my daughter everything she needed. She had a healthy DNA blueprint from her egg donor and her father, but my body gave her life and nurtured her into the human she is. Genetics gave her, her physical appearance (a beautiful one I might add) but epigenetics is what made her who she really is, at her core, her essence, her grit, her compassion. I continue to discover new biological connections I have to her as she grows, which started the moment she was born - my mom kept talking about how much she smelled like me when I was a baby, and at the time I figured it was just a normal baby smell, but later learned it’s an actual biological connection we share."
Read more in this blog post: Nature vs. Nurture: How Donor Egg Babies Can Resemble Their Mother
Not only does epigenetics begin in the womb, but scientists also believe that the most fundamental impact on gene function occurs in utero. A birth mother’s womb serves as the first, and most impactful, environment for the baby. This means that the mother’s lifestyle choices from even before conception, and especially throughout gestation, have a tremendous impact on the overall health of the individual for the rest of their lives. Studies suggest that gene activity may be altered by factors present in the womb even before implantation. This means that the birth mother’s health even before conception can contribute to the overall health of the baby, which is why it is so important to begin prioritizing your health sooner rather than later. Two of the main factors to focus on are controlling stress levels and taking in proper nutrition. If you have any concerns, consult your physician to receive specific health recommendations.
Several studies suggest that the environmental factors that a baby is exposed to in utero have a direct impact on whether that individual develops major medical conditions in their adult life. It's very well-supported that environmental conditions in the womb can have long-lasting effects on development and future health, even into adulthood. For instance, we know that low birth weight is linked to an increased risk of type 2 diabetes and heart disease later in life. (2)
Although a donor egg recipient mother does not contribute maternal genes to the baby, she still has a profound influence on how the baby’s genes will perform throughout the individual’s entire life. The birth mother is responsible for more than just the gestation and birth of the baby. She is responsible for creating a healthy environment for the embryo to develop in; an environment that will contribute to how the baby’s genes develop and the future health of the child.
Below, we share text written by a two-time mother via egg donation, Victoria Nino, on the donor egg pregnancy experience:
"When an embryo implants, the uterine wall sends messages to the embryo to start activating genes, and RNA molecules are sent to the embryo from the uterine wall that activates lots of cool stuff.
My role of growing my babies in my womb is a very important one, and without me, they wouldn’t be them. They’d be different humans. We used to think DNA was the only way to pass on inheritance - but now we have transgenerational epigenetic inheritance - the transmission of epigenetic markers from parent to child that affects the traits of the offspring without altering the primary structure of DNA.
That’s a pretty special connection only we have.
During pregnancy, there is a physiological exchange between the woman carrying and the fetus through the placenta and therefore the carrying woman may have cells from her fetus in her maternal tissue, and these cells could live in your body for a decade or even longer. This is called Fetal Maternal Microchimerism. For women considering using donor eggs, this is yet another scientific explanation that shows the incredible connection you establish with your baby during pregnancy.
It is said that during pregnancy if the mother suffers from organ damage, the baby in the womb sends stem cells to repair the damaged organ. When I was pregnant with my daughter for 39 weeks, our cells merged from my bloodstream and back to hers in the most beautiful dance. She healed parts of me that no one else could. Every child I’ve been pregnant with, even the ones who didn’t make it earthside, has left an imprint on my body. That is something so magically special I will forever be grateful for."
We hope this blog helped understand epigenetics and the significant role it plays in the donor egg IVF process. We aim to provide any parents considering or pursuing donor egg IVF with a multitude of resources to guide them through their unique family-building journey. Please feel free to click around our website for additional resources!
Donor Nexus is a boutique egg and embryo donation agency located in Newport Beach, California, working with egg donors and intended parents worldwide. Since our establishment in 2012, we have helped grow over 1,100 families using donor eggs or donor embryos. We offer free access to our online donor database, high success rates, flexible programs, and exceptional patient care.