Updated on May 18, 2022

Are we losing eggs every day!?
The functions of the ovaries that you might not know

  • egg
  • ovaries
  • AMH

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Are we losing eggs every day!? What is the function of the ovaries?

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Dr. Masahide Shiotani, Chairman of the Board, Ei Women's Clinic

Dr. Masahide Shiotani, Chairman of the Board, Ei Women's Clinic

Supervision

Chairperson of the Board, Ei Women's Clinic
​Professor Masahide Shiotani

After graduating from Shimane Medical University in 1985, she joined the Department of Obstetrics and Gynecology at Kyoto University. At Kyoto University, she belonged to the in vitro fertilization team and pursued research while working on the clinical aspects of infertility, earning a PhD in Medicine (Kyoto University) in 1994. Her research theme was the analysis of the implantation process of fertilized eggs. From 1994 to February 2000, she worked at Kobe Central Municipal Hospital. During this time, she contributed to the birth of the first baby conceived through intracytoplasmic sperm injection (ICSI) in Hyogo Prefecture. In March 2000, she opened the Ei Women's Clinic, a specialized infertility clinic.

The two functions of the ovaries

Illustration of a woman who is troubled.

Where exactly are the ovaries located in the body? I have a general idea of where the uterus is, but...

Professor Masahide Shiotani

They're actually located lower down than you might think. They're a little above the groin area, on both sides.

Illustration of the uterus and ovaries

Illustration of a woman who is troubled.

It's surprisingly located quite far down the list.
What functions do the ovaries perform?

Professor Masahide Shiotani

The ovaries have two main roles.

The first is "the role of preserving eggs."

Women are born with approximately 2 million eggs. Throughout their lives, the ovaries play a role in preventing too many eggs from growing (developing) at once, so that they are released gradually.
Actually, the hormone that plays a role in suppressing the growth of these eggs is called AMH.

If the growth of the eggs were not suppressed, the 2 million eggs a person is born with would grow and disappear all at once, so this plays a very important role.

The second is "the role of secreting female hormones."

During puberty, the ovaries begin to secrete female hormones, and ovulation starts. This is called menarche. As female hormones are secreted, part of the egg begins to grow, preparing it for ovulation.

There are two types of female hormones: estrogen and progesterone. They are known to play a role in maintaining health, such as strengthening bones and preventing arteriosclerosis, as well as in forming feminine physical characteristics.

The number of eggs decreases every day.

Illustration of a woman

So the ovaries are protecting our bodies!
Is it true that the increased frequency of menstruation compared to the past negatively impacts the likelihood of getting pregnant?

Professor Masahide Shiotani

That's right. For example, during the Edo period, women married in their teens and experienced pregnancy, childbirth, and breastfeeding multiple times, so it is said that they had long periods when they were not ovulating.
On the other hand, it is undeniable that modern times are an era of more frequent ovulation due to later marriages. In fact, the increased frequency of ovulation leads to excessive secretion of female hormones, resulting in an increase in gynecological diseases such as endometriosis and uterine fibroids.
These kinds of gynecological problems are also one of the causes of decreased fertility.

※
Fertility
This refers to the ability to conceive. It concerns both women and men and includes the functions of eggs, sperm, reproductive organs, and the endocrine system.

Illustration of a woman who is troubled.

Besides illness, are there any other effects on the number of eggs due to an increase in ovulation frequency?

Professor Masahide Shiotani

Having frequent ovulation doesn't necessarily mean that it negatively impacts the number of eggs produced.
Some patients worry that "inducing ovulation will cause their eggs to run out quickly," but in reality, the number of eggs that naturally decrease each day is far greater than the number of eggs that are ovulated.

Even if you don't get pregnant, about 500 eggs are released from the ovaries during ovulation. In fact, we are born with about 2 million eggs, but by the time we reach around 50, most of them are gone, and menopause occurs. In other words, dozens of eggs are lost every day, even without any intervention.

The rate at which eggs decrease varies from person to person.

Illustration of a woman

I'm surprised to learn that the number of eggs decreases every day!
Is the rate of decrease the same for everyone?

Professor Masahide Shiotani

By measuring the hormone AMH, which suppresses egg growth, it is possible to estimate how many eggs remain (ovarian reserve). The rate at which eggs are lost varies from person to person and is thought to be influenced more by innate physical characteristics than by lifestyle.
I recommend finding out your AMH level from a young age. In fact, Fukuoka City is promoting a service where women aged 30 can get an AMH test for just 500 yen.

Illustration of a woman who is troubled.

The rate at which eggs decrease varies from person to person.
But what if I don't have enough eggs...? That's worrying.

Professor Masahide Shiotani

Here's something important to tell you. What's actually crucial for a body that's more likely to conceive is not the number of eggs, but the "quality of the eggs." Next time, I'll talk about this in more detail.

Illustration of a woman

Egg quality? I'm very concerned about that...
See you next time!

Is "quality" more important than quantity when it comes to eggs?
4 things you can start doing now to help with your fertility journey

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