Egg Lifecycle: How Many Eggs Does a Woman Have and When Do They Run Out?

1. The Female Egg Lifecycle Every woman is born with all the eggs she will ever have. Unlike men who produce sperm throughout life, women's eggs steadily decline in both quantity and quality over time. This presentation explores the remarkable journey of a woman's eggs from before birth through menopause.

2. The Beginning: Before Birth 6-7M 1-2M Peak Egg Count At Birth Around the 20th week of gestation, a female fetus has 6-7 million immature eggs (oocytes) in her developing ovaries. By birth, natural attrition reduces this number to approximately 1-2 million eggs. This represents the only time in a woman's life when new eggs are formed. This finite egg pool marks the beginning of a lifelong countdown.

3. Childhood to Puberty Continuous Decline The number of eggs continues to decrease throughout childhood. Puberty (Ages 9-14) By puberty, only 300,000-400,000 eggs remain in the ovaries – a fraction of the original number. This marks the beginning of monthly menstrual cycles and reproductive capability.

4. Ovulation: The Monthly Process Egg Selection Dominant Follicle Several eggs begin maturation each Usually only one egg becomes dominant month Atresia Ovulation Unused eggs are reabsorbed by the The mature egg is released for potential fertilization body A woman typically ovulates only 400-500 eggs throughout her reproductive lifespan – a tiny fraction of her initial egg supply.

5. The Steady Decline: Quantity and Quality Age 30 Age 37 Quality Issues Older eggs are more prone to chromosomal abnormalities Approximately 100,000 eggs remain Further decline to about 25,000 eggs Fertility begins to wane subtly in the early 30s and more steeply after age 35, as both egg quantity and quality decline.

6. Perimenopause: The Transition Phase Perimenopause occurs several years before menopause when fertility is declining but not completely gone. During this time: • Ovulation becomes irregular • Hormone levels fluctuate dramatically • Symptoms like mood swings and hot flashes may occur • Conception is still possible but increasingly challenging

7. Menopause: The End of the Egg Story Definition Menopause is clinically defined as 12 consecutive months without a menstrual period. Average Age: 51 At menopause, the egg pool is nearly depleted with fewer than 1,000 eggs remaining, most non-viable. Hormonal changes cause menstrual cycles to become irregular before stopping altogether. At this stage, natural pregnancy is no longer possible.

8. Factors Influencing Egg Lifespan Genetics Lifestyle Family history can influence the age at menopause Smoking is known to accelerate egg loss Health Conditions Environmental Exposures Some medical treatments and health conditions can harm eggs Radiation or toxins may impact ovarian reserve These factors can either speed up or slow down the rate of egg depletion.

9. Fertility Preservation Options Egg Freezing Also known as oocyte cryopreservation, this involves harvesting and freezing eggs at a younger age for future use. Assisted Reproductive Technologies In vitro fertilization (IVF) and other treatments can help women conceive when natural fertility is diminished. Donor Eggs An option when a woman's own eggs are no longer viable.

10. Summary: The Lifespan of a Woman's Eggs 1 Before Birth 6-7 million eggs produced during fetal development 2 At Birth 1-2 million eggs remain 3 Puberty 300,000-400,000 eggs 4 Reproductive Life Only 400-500 eggs are ovulated 5 Age 37 Approximately 25,000 eggs 6 Menopause (~51 years) Fewer than 1,000 eggs, mostly non-viable Understanding this timeline empowers women to make informed choices about their reproductive health.