As explained in the section in the introduction to fertility (which we strongly recommend reading), not only does the number of eggs retrieved in women drops with age, but also the quality. When people talk about a drop in the quality, they mean a drop in the ration of good to bad eggs. It doesn’t mean that all eggs get worse. In other words, it means is that for me to find a good egg, I will need to gather a greater quantity of them.
When doctors talk about a bad egg, what they mean is that it is ANEUPLOID. Aneuploidy is a term that makes reference to an abnormal number of chromosomes.
With age, in females, the risk of an egg having more or maybe less than 23 chromosomes increases. If this egg, with an abnormal number of chromosomes, is fertilised by a sperm with 23, the end product (the embryo) is not going to have the correct genetic information (either too much or too little).
Thankfully the majority of embryos with an abnormal number of chromosomes does not implant (this is why infertility increases with maternal age), the few that do will miscarry (for this reason miscarriage also increases with maternal age), and the vast minority might develop into a baby with problems (Down’s syndrome, Patau, Edward’s, also increase with maternal age)
In this graph we can see how the percentage of bad embryos (called ANEUPLOID in medical terms) formed from eggs at different female ages, increases with age.
Sadly, not only does the ratio of good to bad eggs declines after certain ages, the number of eggs we get from stimulating the ovaries also declines.
So, as women’s age increases, we get less good eggs in proportion and also get less eggs in number. This in turn makes it harder to produce a normal embryo, and this is the explanation why IVF success decreases with age.
In these patients egg donation is their only option. The idea of egg donation is to get eggs from a girl younger than 35 y.o.a. At that age, a much greater proportion of eggs has the correct number of chromosomes (bookshelves). And this is why egg donation success rates remain steady, no matter the age of the woman receiving these eggs.
This graph shows how IVF success rates decrease with maternal age while the ones with egg donation remain constant.
Egg donation will always be considered the last resort, the plan “B”, but with a 50-60% percent chance of giving a couple a healthy child, it is a great plan “B” to have!
But what does it mean to use the eggs from another person? I like to compare egg donation to the use of a mold or template to produce a face mask. If I had to make 10 face-masks that were identical, I would probably carve the face in a wooden block that I would then fill with clay. Once the clay dries, I would remove it from the block of wood and that would be my face mask. This is exactly what egg donation is! We would use the donor’s genes (a donor chosen by the couple, a donor that looks very similar to the future mother, a donor that has gone through a very thorough screening process, a donor that has had kids of her own previously, a donor that we thank deeply for helping other couples achieve their dreams) and the male partner’s genes to produce that template. 100% of what will produce the face mask (100% percent of the baby) comes from the mother, not from the donor. Every single cell, protein, down to the last little hair comes from the mother’s body.
Thousands of women are opting more and more for egg donation. As this study showed, the increase in treatment with egg donation has drastically increased over the past years. This is a reflection, not only of an increase in our age when trying to conceive, but also an acceptance, a change in cultural opinion about egg donation.