Every woman is born with all the eggs you are ever going to have in your life. No new eggs are developed during your lifetime; in fact, this is the only time you have the largest number of eggs. You might have heard the term “A woman’s biological clock,” but have you wondered why it only applies to women, not men? The story for men and women is different here, as man makes sperm virtually at the same rate throughout their lives, but women shed their eggs with each menstrual cycle.
You are at your most fertile during your 20s through your mid-30s. Fertility rates drop off after the age of 35 years until menopause. After menopause, it is not possible to get pregnant naturally. In this blog, we will explore how many eggs a woman has at different stages in her life, how and why they decline, and when a woman essentially “runs out” of eggs.
As we already said, your reproductive story begins a you are born. During your fetal development, if we speak specifically, it is around the 20th week of gestation, the ovaries of the female fetus contain the highest number of eggs. This is the only time in her entire life to have the maximum number of eggs, i.e, approximately 6 to 7 million immature eggs, called oocytes, nestled within her developing ovaries. This is the peak egg count.
However, this number soon begins to decline sharply even before birth. By the time the baby girl is born, the number of eggs has already dropped to about 1 to 2 million. It is a natural attrition—a process where many eggs degenerate and die off before she even takes her first breath. Unlike males, who continually produce sperm throughout their lives, females do not generate new eggs after birth. This finite egg pool marks the beginning of a lifelong countdown.
After birth, the number of eggs decreases continuously during childhood. By the time you it your puberty, usually at the age between 9 to 14, the number of eggs remaining in the ovaries is around 300,000 to 400,000. While this is still a large number, it is a fraction of what she started with before birth.
During puberty, the body begins monthly menstrual cycles, signaling the start of reproductive capability. Each cycle, several eggs start the maturation process in the ovaries, but typically only one egg becomes dominant and is released during ovulation. This monthly release is what makes natural conception possible.
On average, a woman ovulates once every menstrual cycle—approximately once a month. Over her reproductive lifespan, a woman will typically ovulate between 400 to 500 eggs. It’s important to realize how small this number is compared to the millions of eggs she started with.
Most eggs that begin to mature each month do not complete development and are instead reabsorbed by the body in a process called atresia. Atresia is a natural form of egg loss that happens throughout a woman’s life, whether she ovulates or not.
One of the most crucial aspects that you need to understand about female fertility is that it not only decreases the number of eggs but also impacts their quality, which declines over time. Here, the quality of eggs refers to the genetic health of eggs and their ability to support embryo development and fertilization.
At the time you are achieving you age of 30, the number of eggs has dropped to approximately 100,000, and at the age of 37, it is going to decline further to 25,000. The decline generally accelerates as a woman is going to ages, as the quality of eggs is progressively affected due to certain factors like genetic, environmental, and lifestyle factors. This decline clearly explains why fertility begins to wane subtly in the early 30s and more steeply after age 35.
Here, the chances of conception generally decrease as only a few good quality eggs remain which making it difficult to fertilize. Older eggs are more prone to chromosomal abnormalities, leading to higher risks of miscarriage and conditions like Down syndrome.
Menopause is a stage when a woman hits, it marks as the end of her natural reproductive phase. It is clinically proven that a woman has gone without her menstrual period for more than 12 consecutive months. Generally, it occurs at an age of 51, if we talk about the average age, as it can vary widely depending on factors.
When a woman is diagnosed with menopause, the pool of her eggs is nearly depleted, and few of the 1000 eggs that are left are also not viable. During this phase, the hormonal changes that occur cause menstrual cycles to become irregular before they stop altogether. Thus, a natural pregnancy is not possible when a woman hits this age.
Hormonal changes during this time cause menstrual cycles to become irregular before stopping altogether. At this stage, a natural pregnancy is not possible.
Premenopause is a stage that a woman undergoes several years before she hits her menopause. This lasts for several years when her fertility is declining, but has not gone competently. During this ovulation becomes irregular and hormone levels fluctuate drastically, which causes symptoms like mood swings and hot flashes. Women can conceive during their perimenopause, but it becomes challenging for them as many of them do not reliable that their fertility window is getting reduced and may close anytime.
While the egg lifecycle broadly follows the pattern above, certain factors can speed up or slow down the rate of egg depletion:
As we already know about several fertility preservation options, they are considered of the utmost priority as people are increasingly aware of the decline in the natural fertility process. In this, Egg Freezing is one of the most common methods, also known as oocyte cryopreservation, which involves harvesting and freezing eggs at a younger age for future use.
In those cases where natural fertility is exhausted, assisted reproductive technologies (ART) like in vitro fertilization (IVF) are treatments that can help women to conceive. You can also go for using donor eggs if your eggs are not that viable.
If you are interested in understanding your own fertility or egg reserve, you can consult a healthcare practitioner at Aveya IVF Center. They will help in recommending tests such as Anti-Mullerian Hormone (AMH) levels or antral follicle count via ultrasound to estimate ovarian reserve.
The female egg lifecycle is a remarkable biological timeline marked by the natural decline of both quantity and quality of eggs over time. It highlights why age is a central factor in fertility and why timely planning is important for women who wish to have children.
Whether considering starting a family now or preserving fertility for the future, understanding the limits of the egg reserve empowers women to make informed choices about their reproductive health.
If you have further questions or want to explore topics like fertility testing, preservation techniques, or assisted reproduction, feel free to ask Aveya IVF Centre!