How many eggs do women have?

Women are born with about 6 million eggs in their ovaries, losing thousands of them each month and by menopause having less than 100 eggs left.

From birth to puberty

Every girl is born with a certain number of eggs and no new eggs are produced during her lifetime. At this stage, the immature eggs are called oocytes. Egg cells are located in follicles (fluid-filled sacs) in the ovaries. As they grow, they become oocytes and develop into an ovum, or mature egg.

During early fetal development, a baby girl's ovaries contain about 6 million eggs. The number gradually decreases until by the time the baby is born, they have 1-2 million remaining. egg

Menstruation doesn't begin in girls until puberty, about two years after breast tissue appears. At that time, the hypothalamus in the brain begins producing gonadotropin-releasing hormone (GnRH). GnRH stimulates the pituitary gland to produce follicle-stimulating hormone (FSH). FSH starts the process of egg development and causes estrogen levels to rise. The average age of menstruation is around age 12, but some girls may start as early as age 8.

At puberty, each girl has only about 300,000-400,000 eggs . This decrease is due to the death of more than 10,000 eggs each month before puberty.

As the follicles mature, they become sensitive to hormones during the menstrual cycle. Each month, the body selects a group of mature eggs to release, but only one egg is eventually released, representing a woman’s only chance of conceiving each month. In some exceptional cases, more than one egg is released, resulting in twins.

All the remaining eggs in that cycle's pool wither and die. This happens every month and continues until a woman reaches menopause, when she no longer has any eggs.

The number of eggs that die each month decreases after puberty. According to Sherman Silber, an infertility specialist in the US, a woman loses about 1,000 immature eggs each month after the start of her menstrual cycle. Research data is still unclear on whether health conditions and foods affect the quality or quantity of eggs. According to a 2018 study by the American Society for Reproductive Medicine, smoking and some chemotherapy and radiation treatments can speed up ovulation.

Women's fertility is best between the ages of 20 and 30, when the quantity and quality of eggs are both high. Photo: Freepik

30 years old and above

According to the American College of Obstetricians and Gynecologists (ACOG), when women turn 30, their fertility begins to decline rapidly. By age 40, their egg supply is less than 10% of what it was before they were born. Research shows that premenopausal women over 40 have less than a 5% chance of getting pregnant in any given menstrual cycle.

When the egg supply runs out, the ovaries stop producing enough estrogen and a woman goes through menopause. The exact timing of menopause depends on how many eggs a person is born with and how often she ovulates. The average age of menopause, when menstrual periods stop, is 51. For some women, menopause can come earlier or later.

According to data from the American College of Obstetricians and Gynecologists (ACOG), at age 37, women have only 25,000 eggs left in their ovaries, and they will reach menopause about 15 years later, when they have fewer than 100 eggs left.

The most important factor in determining egg quality is age. As women age, both the quantity and quality of their eggs decline. Just before ovulation each month, eggs begin to divide. Older eggs are more likely to make mistakes during this division process, making them more likely to contain abnormal chromosomes. When the egg and sperm combine to form an embryo, there is a higher risk of chromosomal or genetic abnormalities. This is why older women are at higher risk of having a baby with birth defects.

If born with a large number of eggs, women are still able to have children naturally in their mid-40s or even late 40s. Those in their 30s who ovulate more rapidly due to certain risk factors may experience early menopause or premature ovarian failure.

If you are concerned about your ovarian reserve or egg quality, you should see a doctor for an examination and assessment of risk factors and advice on treatment. If you plan to have children later, you can consider freezing your eggs. The earlier you freeze your eggs, preferably before age 35, the higher the quality of your eggs, the more you can collect, and the higher your chances of having children.

Anh Ngoc (According to Healthline )

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