Let’s start with what menopause is. It is not something new, but rather the end of something old. And that something is the process of nourishing egg cells to maturity. In fact, it might coincide with the end of egg cells, altogether.
When a girl is born, she has about a million egg cells left, just a fraction of what she had a few months earlier. By the time she hits puberty, she typically has about 400,000 egg cells. What changes at puberty is that she starts to feed those egg cells with hormones from the follicles. A follicle is a group of cells that includes the egg, as well as the cells that will feed it and nurture it to maturity.
From age 12 to age 50-52 (it could come as early as 45 or as late as 55), a woman develops one egg each cycle, or every 28 days, although occasionally an additional egg is developed for twins. It is the hormones in the follicles that nourish the egg and help manage the stages of the menstrual cycle.
Something changes at menopause. The follicles run out of hormones. Yes, there is an expiry date beyond which they are no longer capable of nourishing the egg. The hormones stop flowing. It doesn’t happen all at once, and symptoms of the onset of menopause can continue for 5 or ten years as the hormones slowly run out.
The remaining eggs are abandoned and the menstrual cycle stops.
Well, due to a process called “atresia”, eggs are being destroyed all the time. That’s why a child who begins with millions of egg cells has only one million by birth and 400,000 by puberty. The body will continue to destroy and absorb any leftover eggs that might still be around after menopause, which might be only 100 – or none at all. Indeed, the follicles might run out of hormones, or the body might run out of eggs first. But those eggs that might remain are no longer viable, anyway.
Even approaching menopause, one is no longer an ideal candidate for egg donation. Keep in mind that for women over 40, one of the reasons for using an egg donor and/or a surrogate mother is that their eggs are no longer reliable. In a woman’s late 40s, she might even miss a cycle or two before hitting menopause, as the body finds eggs and follicles that are no longer viable. And in some cases, menopause does start as early as 45 or 46.
Often the eggs at that age will develop and fertilize just fine, but also often they will not. The intended parents want an egg donor with a pretty certain chance that the egg will be suitable for a pregnancy. They are much less likely to take that risk with a 48-year-old donor than with a 25-year-old donor.
Once a woman’s eggs are no longer reliable, she is not a candidate for egg donation.