How Many Eggs Do Women Have?
- Fysiobasen
- 9. nov.
- 3 min lesing
Women are born with a finite number of eggs, and this number gradually decreases throughout life.
This natural process is central to female fertility and reproductive aging.
But what does it mean to have a limited number of eggs, and how does this affect a woman’s ability to conceive?
This article explains how many eggs women have, how eggs develop, and how the number changes over time.
Egg Development Before Birth
Egg development begins long before birth — while a female is still a fetus.
At this stage, the developing baby reaches her maximum egg count, with as many as 6 to 7 million eggs forming in the ovaries during pregnancy.
By the time a baby girl is born, this number has dropped to 1–2 million eggs.
However, most of these eggs are immature and remain in a resting phase called primordial follicles.
Number of Eggs at Birth, Puberty, and Adulthood
At Birth
Newborn girls have around 1–2 million eggs, but they remain dormant until puberty.
Even before puberty, many eggs naturally degenerate and are absorbed by the body.
At Puberty
By the time a girl reaches puberty, only about 300,000–400,000 eggs remain.
This represents a dramatic reduction from birth.
From this point on, eggs begin to mature and are gradually released during each menstrual cycle.
During Adulthood
After puberty, women typically release one egg per month during ovulation, around the middle of each menstrual cycle.
Over a lifetime, only about 400–500 eggs will ever be released.
The rest are lost naturally through a process called atresia, in which unused eggs break down and are reabsorbed.
How the Egg Count Declines Over Time
The number of eggs decreases steadily with age through several biological processes:
Natural egg loss: Even when not ovulating, hundreds of eggs die each month as part of the body’s natural rhythm.
Aging: Both the quantity and quality of eggs decline with age. After the mid-30s, the rate of loss accelerates, and egg quality declines.
Menopause: Around age 50, ovulation ceases. At this point, the ovaries contain very few, if any, viable eggs.
Egg Quality and Fertility
Egg quantity matters, but egg quality is equally important for fertility.
Younger women tend to have higher-quality eggs with healthier chromosomes, increasing the chances of successful fertilization and pregnancy.
As women age, remaining eggs accumulate more genetic errors, raising the risk of miscarriage or birth defects.
Lifestyle factors such as smoking, poor nutrition, obesity, and medical conditions like polycystic ovary syndrome (PCOS) can also negatively affect egg quality.
Can Eggs Be Frozen for Future Use?
Yes — egg freezing (oocyte cryopreservation) is a modern fertility preservation method.
Eggs are retrieved from the ovaries, frozen, and stored for future use.
When the woman is ready, the eggs can be thawed and fertilized through in vitro fertilization (IVF).
However, egg quality is highest when retrieved at a younger age, so earlier preservation increases success rates.
Summary
Women are born with all the eggs they will ever have — about 1–2 million at birth.
By puberty, this decreases to 300,000–400,000, and only about 400–500 are ever released during a lifetime.
The number and quality of eggs decline naturally with age, making conception more difficult over time.
Egg freezing offers an option for extending fertility, but success depends on age and egg health at the time of preservation.
Sources
ESHRE Capri Workshop Group. (2010). The effects of age on female fertility and the impact of assisted reproduction. Hum Reprod, 25(5):1069–1075.
Broekmans FJ, et al. (2006). Female age and the assessment of ovarian reserve. Hum Reprod Update, 12(6):667–680.
Lawson M, et al. (2011). Oocyte cryopreservation: A comprehensive review of the technique and its clinical applications. Hum Reprod Update, 17(5):711–726.
Hunt PA, et al. (2016). Reproductive aging in women: The impact of aging on female fertility and the role of genetic and environmental factors. J Assist Reprod Genet, 33(4):545–554.
Bachelot A, et al. (2015). Female reproductive aging: Causes and consequences. Fertil Steril, 104(2):255–267.
