Age and fertility is a sensitive topic. We don't want to create panic or pressure, but we also believe women deserve accurate information to make informed decisions about their reproductive lives.
The truth is nuanced: age matters a lot, but it's not the only factor. And the statistics that get thrown around are averages that don't account for individual variation.
Why Age Affects Female Fertility
Unlike men who continuously produce new sperm, women are born with all the eggs they'll ever have—about 1-2 million at birth. This number declines throughout life:
- At birth: ~1-2 million eggs
- At puberty: ~300,000-400,000 eggs
- At age 30: ~100,000-150,000 eggs
- At age 40: ~10,000-20,000 eggs
- At menopause: ~1,000 eggs (no longer fertile)
But egg quantity is only part of the story. Egg quality—the genetic integrity of the eggs—also declines with age. As eggs age, they're more likely to have chromosomal abnormalities, which increases the risk of failed fertilization, failed implantation, miscarriage, or chromosomal conditions like Down syndrome.
Fertility Across the Reproductive Years
Fertility by Age Bracket
What to Know
Your 20s are when fertility is at its peak. Egg quality is highest, ovulation is usually regular, and the chance of chromosomal abnormalities is lowest. Most women in this age group who are trying will conceive within 6-12 months.
What to Do
If you're not ready for kids, this is a great time to track your cycle and understand your body. Consider your long-term plans. If you know you want children eventually but not now, you might explore egg freezing in your late 20s when egg quality is still optimal.
What to Know
Fertility is still strong in the early 30s. The decline has begun but is gradual. Most women in this age group conceive without difficulty. This is actually the most common age for first-time mothers in many developed countries.
What to Do
If you're ready to try, go ahead—odds are good. If you've been trying for 12 months without success, it's reasonable to see a doctor. Consider ovarian reserve testing (AMH, AFC) if you want to know where you stand. Egg freezing is still very effective at this age if you're not ready.
What to Know
Fertility decline accelerates after 35—this is the biological reality. Egg quantity drops more rapidly, and the proportion of chromosomally abnormal eggs increases. That said, the majority of women in this age group can still conceive, often naturally. Many healthy pregnancies happen at 35, 36, 37, 38, 39.
What to Do
Don't wait too long to seek help—see a specialist after 6 months of trying (vs. 12 months for younger women). Get a fertility evaluation early. Time matters more now, so be proactive. If you're not ready to try, seriously consider egg freezing—quality declines significantly through this decade.
What to Know
Fertility is significantly reduced after 40, and declines rapidly through the early 40s. By 45, natural conception is rare. The rate of chromosomal abnormalities increases substantially—about 50% of eggs at 40 are chromosomally abnormal, rising to 75%+ by 42-43. This is why miscarriage rates are high.
What to Do
See a reproductive endocrinologist promptly—don't wait. IVF success rates decline significantly after 40, especially with your own eggs. Donor eggs remain highly successful regardless of recipient age. Some women do conceive naturally after 40, but be prepared that it may require medical assistance, and have honest conversations with your doctor about realistic expectations.
Testing Your Ovarian Reserve
If you want to know how your fertility compares to averages for your age, two tests are commonly used:
AMH (Anti-MĂĽllerian Hormone): A blood test that estimates the remaining egg supply. Higher levels suggest more eggs; lower levels suggest fewer. Can be done any day of your cycle.
AFC (Antral Follicle Count): An ultrasound that counts the small follicles visible on your ovaries at the start of a cycle. More follicles generally indicates higher reserve.
These tests measure quantity, not quality. Egg quality can only be assessed through IVF (by embryo grading) or inferred from age. Still, these tests help you understand where you stand relative to others your age and can inform decisions about timing or egg freezing.
Consider ovarian reserve testing if: you're over 35 and planning to delay pregnancy, you have a family history of early menopause, you've had ovarian surgery, you want information to make family planning decisions, or you're considering egg freezing. Insurance often doesn't cover testing for fertility awareness, but it's worth asking.
What About Egg Freezing?
Egg freezing (oocyte cryopreservation) allows you to preserve eggs at your current age for potential use later. The eggs are frozen in time—a 30-year-old's eggs frozen and used at 40 have the success rates associated with age 30.
Ideal timing: Before 35, ideally in late 20s to early 30s when egg quality is optimal and enough eggs can typically be retrieved.
Still beneficial: Ages 35-38, though you may need multiple retrieval cycles to bank enough eggs.
Limited benefit: After 38-40, egg quality has declined enough that success rates are lower and many eggs may be needed.
Egg freezing isn't a guarantee—not all eggs survive thawing, fertilize, or become viable embryos. But it does give you more options if you're not ready to try now.
"The best time to freeze your eggs was 5 years ago. The second best time is now—if you're under 38 and not planning to try soon."
What You Can (and Can't) Control
You can't control:
- Your chronological age
- Your genetic baseline for ovarian reserve
- The natural rate of egg quality decline
You can control:
- When you start trying (timing matters)
- Getting tested to know your status
- Lifestyle factors that support egg health
- Seeking help promptly when needed
- Considering options like egg freezing
Where Are You in Your Journey?
Our quiz can help you understand your situation and suggest next steps.
Take the Fertility Quiz →The Bottom Line
Age is the most significant factor in female fertility—this biological reality exists regardless of how we feel about it. But it's not the only factor, and the statistics are averages that may not apply to you specifically.
Key takeaways:
- Peak fertility is in the mid-20s, with gradual decline starting around 30
- The decline accelerates after 35 and becomes more pronounced after 40
- Both quantity and quality of eggs decline with age
- Most women under 40 can still conceive, many naturally
- Testing (AMH, AFC) can tell you where you stand relative to your age
- Egg freezing is an option if you want to preserve fertility for later
- Seek help sooner if you're 35+ (after 6 months vs. 12 months)
Don't let fear drive decisions, but do let information guide them. Know where you stand, understand your options, and make choices that align with your goals and circumstances.