By age 45, most women have somewhere between 1,000 and 10,000 eggs remaining in their ovaries. That’s a dramatic drop from the roughly 2 million they were born with, and it reflects decades of steady, accelerating loss. But the number alone doesn’t tell the full story. The quality of those remaining eggs changes significantly too, which is why fertility at 45 looks very different from fertility at 35.
How Egg Count Changes Over a Lifetime
A female fetus actually has the most eggs she’ll ever have: around 6 million, early in development. By the time she’s born, that number has already fallen to between 1 and 2 million. At puberty, roughly 300,000 to 400,000 remain. From there, the decline continues through adulthood, with the rate of loss accelerating in the mid-to-late 30s.
At age 37, about 25,000 eggs remain. After that, the pace picks up considerably. Research published in Human Reproduction found that ovarian follicles disappear faster in midlife than earlier models predicted. By around age 51, the typical age of menopause, the count drops to approximately 1,000. That 1,000-follicle mark is widely used as the threshold associated with menopause onset.
So at 45, you’re somewhere between the 25,000 eggs of your late 30s and the roughly 1,000 at menopause. The exact number varies widely from person to person based on genetics, health, and other factors. But the trajectory is consistent: loss accelerates sharply after about age 40.
Why the Number of Eggs Only Tells Part of the Story
Even if thousands of eggs remain at 45, the vast majority carry chromosomal abnormalities. Analysis of over 15,000 embryo biopsies showed that by age 43, about 85% of eggs are aneuploid, meaning they have the wrong number of chromosomes. These eggs are far less likely to result in a healthy pregnancy. At 45, the percentage is at least that high, possibly higher.
This is the core challenge of fertility at this age. It’s not just that you have fewer eggs. It’s that the eggs you do have are much less likely to function normally. Chromosomal errors in eggs increase the risk of failed implantation, miscarriage, and genetic conditions like Down syndrome. Even when thousands of eggs are technically present, only a small fraction are viable.
How Doctors Estimate Your Remaining Supply
There’s no way to count eggs directly, but two common tests give fertility specialists a useful picture of where things stand. The first is a blood test measuring a hormone produced by the small follicles in the ovaries. At age 45, a typical reading is around 0.5 ng/mL, which is well below the levels seen in younger women and signals a significantly reduced reserve.
The second is an ultrasound that counts visible follicles on the ovaries. Research tracking women from age 25 to 45 found that follicle counts decline by roughly one follicle per year in younger women, but after about age 40, the rate nearly doubles to about two follicles per year. By 45, most women have noticeably fewer visible follicles than they did even five years earlier. Neither test tells you exactly how many eggs remain, but together they give a reliable sense of your ovarian reserve relative to your age.
What This Means for Getting Pregnant at 45
The combination of fewer eggs and lower egg quality makes natural conception at 45 uncommon but not impossible. The estimated chance of getting pregnant in any given menstrual cycle is about 2 to 3 percent by the late 40s. For comparison, a woman in her early 20s has roughly a 25 to 30 percent chance per cycle.
IVF with your own eggs at 45 also faces steep odds. Because so many eggs retrieved will be chromosomally abnormal, it often takes multiple cycles to find even one viable embryo. The largest single-center study of IVF in women 45 and older, which analyzed over 1,000 cycles, confirmed that the high rate of chromosomal errors is the primary barrier, not just egg quantity. Many fertility clinics recommend using donor eggs for women in this age range because donor eggs from younger women bypass the quality problem entirely and yield much higher success rates.
Factors That Affect Your Individual Count
While the general timeline applies to most women, individual variation is significant. Genetics play a major role: if your mother or sisters experienced early menopause, your egg supply may decline faster than average. Smoking accelerates follicle loss and can push menopause earlier by one to two years. Ovarian surgery, certain chemotherapy drugs, and some autoimmune conditions can also reduce the egg reserve ahead of schedule.
On the other hand, some women maintain a higher-than-expected reserve into their mid-40s. This doesn’t necessarily mean their eggs are higher quality, but it can mean they have more time before menopause and potentially more opportunities for conception. If you’re 45 and curious about where you stand personally, the blood and ultrasound tests described above are quick, widely available, and can give you concrete numbers to work with.