A woman’s reproductive system is fascinating and all too often misunderstood. Many of us know it involves a monthly cycle of hormone changes, ovulation, and either a shedding (if unfertilized) or conception (if successfully fertilized) of the ovulated egg.
But what do eggs have to do with the female body? How many eggs does a woman have at the varying stages of her life?
Ovarian Egg Development During Female Gestation
A human female is born with a non-renewable supply of egg cells in her ovaries. It’s estimated that up to 6 million eggs are produced within the gestating embryo by around 20 weeks of the mother’s pregnancy. By the time the baby is born, the number of eggs is closer to 1 or 2 million.
Unlike sperm (the gametes of a male), it’s widely understood that females don’t create new eggs after nonviable eggs die off. The amount of eggs a female baby is born with is the highest amount she’ll ever have.
Despite being born with so many eggs, only 300-400 eggs will reach ovulation. That’s quite a lot of non-regenerative loss women experience. And usually, we aren’t even aware of it! This is one of the many amazing scientific phenomena of the female body, and it’s important to understand if you’re considering your fertility.
How Many Eggs Do Females Have at Puberty?
During childhood, immature eggs (called oocytes) are stored in fluid sacs in the ovaries called ovarian follicles. The body waits for eggs to mature during puberty. Even before adulthood, these follicles experience a decline. As prepubescent children, females are constantly losing eggs—usually up to 10,000 per month.
When a female reaches puberty, nearly 300,000 of her eggs are left. Every month, some of the eggs mature and prepare for ovulation. In most cases, only one egg will become successfully mature (called an ovum) and release from the ovary to finally ovulate.
The other eggs that prepared but failed will be naturally lost. The only exception to this is if one or more eggs are successfully ovulated and then fertilized at the same time, which results in fraternal twins or triplets.
How Many Eggs Do Women Have as Adults?
Every woman is different, and therefore so is her reproductive cycle and egg status. Depending on things like genetics, hormones, contraception, and lifestyle, different women can have a different number of eggs throughout adulthood.
On average, in the early 20s, about 15% to 20% of immature eggs remain from birth. That’s about 150,000 to 250,000 total. After puberty, the average woman loses 1,000 or more egg follicles each month.
Throughout the 30s
It’s a commonly known fact that once women reach their 30s, their eggs begin to decline more rapidly. The chances of fertility drop dramatically and it can become difficult for some women to conceive. This doesn’t mean it’s impossible to conceive—in fact, plenty of women still give birth after the age of 30. Biologically, it’s just not as common.
Usually by their mid-30s women have an average of 70,000 to 150,000 oocytes remaining. After that, the eggs decline even more rapidly.
Ages 40 to 50
During your 40s and 50s, the body focuses less on reproduction as the number of eggs is few and the body begins to prepare for menopause. A 45-year-old woman usually has fewer than 18,000 eggs left.
Women can still get pregnant, especially with the help of medical interventions such as IVF (Invitro Fertilization). But it’s rare.
Menopause typically happens between the ages of 50 and 60 after the body stops having a menstrual cycle. Hormones change, eggs stop ovulating, and the body prepares for the later stages in life.
Perimenopause, the sometimes decade-long phase leading up to menopause, can involve changes to a woman’s eggs and her cycle. Periods can be less or more frequent, ovulation may decrease, and estrogen and progesterone (the female sex hormones) can grow out of balance. Eventually, the last egg will mature and the woman’s menstrual cycle will naturally come to an end.
Can Lifestyle Contribute to Egg Loss and Fertility Concerns?
Some experts believe that lifestyle can prevent rapid egg loss. This is often called Diminished Ovarian Reserve. Some factors that contribute to this are:
- Some types of birth control
- Cancer treatments (radiation or chemo)
- Major surgery such as a hysterectomy or endometriosis
How Can a Woman Save Her Eggs?
If a woman is concerned about having children later in life, there are medical options that can improve the chances of conception. Egg freezing is a popular choice, which preserves healthy, younger eggs for conceiving beyond 30.
Talk to your fertility doctor if you have any questions or concerns about your eggs. With modern medicine, there are many resources available to make sure you make the best reproductive choices for your body and situation.