The ovarian reserve: are there only 400 chances of conceiving?

The other day I saw on the website of women's magazine "Lady Pravda" one article on issues of relations between men and women. Actually, i would have passed it by, but I was intrigued by one part there, and I quote it now:

"The female reproductive system is drastically different from the men’s one. Our eventual choices produce up to 12 million spermatozoa per hour, and if you count how much semen is formed in male germ gland during their lifetime, you will get the cosmic digit - a few trillions! If every man's semen could evolve into the embryo, there would be no place to live on our tiny planet. It's frightening to imagine the number of women that our hypothetically faithful beloved could fertilize. Completely different story is with the female physiology – there are just 400 eggs for the whole life. So our gametes are the greatest value of nature."


It's hard to deny the fact that the average number of matured woman’s eggs which can be used for fertilization is about 400 during the whole reproductive period. If the sperm of men is a renewable resource, the women’s eggs are not. But as for the capacity of men’s ones, let me disagree, especially since this topic is directly related to IVF. I would like to discuss it a bit later, but first- here are some general knowledge about human anatomy and physiology.

The supply of eggs (ovarian or follicular reserve) is different at each woman’s. By the fifth month in the female embryo the number of germ cells is about 6-7 million. Subsequently, the number of follicles (vesicles that contain a future egg) is reducing- so by the time of the birth the female baby has 1-2 million of them left, and to the first menstrual period – there are no more than 500,000 left. Yes, for sure 500,000 can’t be compared with the billions of spermatozoa, produced at the man’s body throughout his life. Well, but it’s still more than 400.

And a few words about processes that happen to a woman every month. Most of people know (or at least should know), that usually woman’s ovaries work, so to speak, in a turn: when the one is responsible for reproductive functions, the second recreates, afterwards they change. So, the ovary, which "is awake" at this cycle, generates a certain quantity of follicles that start to grow. This amount depends on the woman’s total ovarian reserve that accordingly decreases with age. So follicles start to grow. But only one of them, the best developed, attains the stage of ovulation – a process when an egg breaks the follicle and releases from the ovary into the cavity of the female reproductive organs, where an egg is waiting for fertilization. The rest of the "losers" pass the reverse stage of development - atresia – and simply stay in Bose.

Now I want to explain what made me write this post. First, of course, the offense for the male reproduction :-). In fact the nature programmed everything so that most of genetic material, both male and female, is wasted (or rather, we believe that it is wasted - in fact, some necessary natural mechanisms in this can be hidden, but we  just do not know anything). But in the end, everything happens so that a single spermatozoa meets his one and unique egg which leads to the mystery of conception. And there is no sense to count the amount of genetic material that “remained out of work”.

By the way, it’s curious that a conception is not made by the fastest spermatozoa, as it’s usually considered. It’s the other way around: the fastest one dies trying to break through the wall of an egg cell, thereby softening it and paving the way for the lucky one. So you can not say that these tens of millions of semen are not useful. But that's another story.

To be honest, when I’ve read this fragment, I thought that now, perhaps, the same article of Madame Peterkina was being read by a woman, who had decided to go through the procedure of IVF, which, as you know, might require 10 and even 20 mature eggs at once. It means that it is necessary to lay out 3-5% of their ovarian “wealth” just for 1 procedure? As for an egg donation, it should be evaluated not in rubles or dollars, but in diamonds.

But don’t panic: everything is not so tragic. The point is that one of the basic components in the IVF procedure - is to stimulate superovulation. It is made with medication to help follicles, produced during the cycle in the woman’s body to become full-mature oocytes. It means that we use the reserve stock of a woman’s organism, which otherwise is just gone without any use. Thus, the "counting the losses" should be done not from 400 eggs, but from 500 000 potential ones. And this, as you see, is quite another arithmetic.

Finally, I would advise the author to be more careful with quoting numbers. As it’s said, we can not predict how our words resound after...