When talking about female fertility, particularly with those interested in egg freezing, one of the most common questions asked is, “how many eggs does a woman have?” Or, more specifically, “how many eggs do I have?” That’s a good question, but the answer is highly dependent upon what time in the woman’s life you are talking about as well as individual variances. And because there is so much natural variation between women, it’s important to know what you can do to test your own egg reserve. And what about egg quality? Are quantity and quality related?
Those are all great questions, so let’s get started.
The peak number of eggs a woman ever has takes place at about 20 weeks of gestation (before they are born and still inside their mother’s womb). At this point, they have roughly 6-8 million eggs. No new eggs will ever be made from this point on.
Egg cells are constantly degenerating and go through a cell death process known as atresia.
Starting with puberty, a new batch of eggs are selected every day to start developing. The number of eggs that leave the “waiting pool” each day is highly dependent upon the age of the woman.
During peak reproductive years, roughly 30-40 eggs will leave this waiting pool and start to develop each day (a thousand a month). Of these, only 1/10th will enter a menstrual cycle and typically only one egg is developed fully and ovulated.
Because many eggs start to develop but die off before being ovulated, a woman goes through roughly 300,000-400,000 eggs in their reproductive years, but only ovulates 300-400 eggs.
The average woman runs out of eggs and starts menopause around the egg of 52.
Egg quality, though not directly related to quantity, is correlated. As a woman ages, both their egg quality and quantity generally decline.
How Many Eggs Does a Woman Have at Birth?
A woman is typically born with around 1-2 million eggs in their ovaries. Unlike men who are always producing new sperm to replenish their sperm count, females stop making eggs. What’s even more unexpected is that females will have produced all they eggs they will ever make by 20-weeks of gestation (halfway through the pregnancy). Usually, that number is around 6-8 million.
How Many Eggs Does a Woman Have At Puberty?
Even though a female doesn’t typically start menstruation and have the ability to get pregnant until they are between the age of 10-15, eggs are constantly degenerating and being lost throughout infancy and adolescence. As a prepubescent female, approximately 10,000 eggs will degenerate and “die” each month. That means by the time a woman reaches puberty, they only have 300,000-400,000 eggs left in their ovaries.
How Many Eggs Does a Woman Have at 30?
Of course, there is a great deal of variation in women; some are tragically diagnosed with primary ovarian inefficiency (POI aka premature ovarian failure) in which a woman runs out of eggs while in their 20s or 30s, while other women are blessed with an incredibly high ovarian reserve even well into their thirties and even forties.
Of course, when speaking generally about how many eggs a woman has in their 30s, we’re talking averages and estimates. Women in their early thirties are generally better off than women in their late thirties as ovarian reserve declines sharply in the late thirties. For example, a woman at 30 often has around 100,000-150,000 eggs in reserve. By 35, that number is likely around 80,000. Late into the thirties, that number could be 25,000, 10,000, or fewer.
How Many Eggs Does a Woman Have at 40?
After the rapid decline in egg count starting around age 37, by the time a woman hits 40, their ovarian reserve is often estimated to be around 5-10,000. But again, there are no one-size-fits-all answers here. While the chance of getting pregnant in the 40s is generally quite low, there are women who conceive naturally well into their 40s and even more who do so with IVF or donor egg IVF.
How Many Eggs Does a Woman Have at 50?
By 50, women are likely to only have a few hundred if any eggs left at all. The average age of menopause is around 51-52 years of age, though smoking and other factors may cause the onset of menopause earlier . Chemotherapy and radiation notably have a very toxic effect on egg quantity.
When eggs run out, the ovaries cease to make estrogen, and the woman will start menopause.
This article was written by CNY Fertility.