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There is a lot of noise around age, fertility, menopause and peri-menopause in general. You may have heard that fertility “falls off a cliff” from the age of 35. You may also have been told that women can have children well into their 40s.

There are plenty of advertisements for tests that promise to tell you how many fertile years you have left. However, the reality of your age and your fertility is a lot more nuanced.

Women can and do have healthy pregnancies in their late 30s and 40s. But can also struggle to fall pregnant during their 20s. While female fertility does change with age, everybody’s experience is different. Understanding that change can help you make decisions based on your own biology rather than the fear, pressure or misleading fertility myths spread throughout the media.

Age is not the only factor that determines whether someone will become pregnant. Ovulation, fallopian tube health, the health of your partner/donor, sperm quality, underlying conditions, previous surgery, endometriosis, PCOS and your own overall health can all influence fertility.

Taking all of this into account, age remains one of the strongest predictors of female fecundity (the probability of becoming pregnant in a given menstrual cycle).

So, what actually changes as we get older?

Fertility Doesn’t Suddenly Disappear At 35

One of the most common fertility myths is that something dramatic happens to a woman’s fertility on her 35th birthday. It doesn’t.

Fertility generally begins to decline gradually during the early 30s, with the decline becoming more noticeable through the mid-to-late 30s and particularly into the 40s. Research following women trying to conceive naturally has found a progressive reduction in the probability of conception with increasing female age.

In one prospective study of women aged 30–44 (Dunson, Colombo & Baird, American Journal of Obstetrics and Gynecology, 2002), women aged 30–31 had an estimated 87% cumulative probability of pregnancy within 12 cycles, compared with 71% among women aged 38–39 and 54% among women aged 40–41.

These figures are population estimates—not predictions for an individual woman.

Some women will conceive quickly at 39. Others may struggle at 25. Your age provides important information, but it does not tell your entire fertility story.

The Two Big Changes: Egg Number and Egg Quality

When we talk about fertility and age, two concepts are particularly important: ovarian reserve and egg quality.

Ovarian Reserve: How Many Eggs Remain?

Women are born with their lifetime supply of eggs. Unlike sperm, which are continuously produced, the number of oocytes in the ovaries decreases over time. This is called ovarian reserve.

As age increases, ovarian reserve generally decreases. However, women of the same age can have very different ovarian reserves. This is one reason why age and fertility cannot be reduced to a single number or test result.

Tests such as anti-Müllerian hormone (AMH) and an antral follicle count (AFC) can provide information about ovarian reserve. They can be particularly useful when planning fertility treatment because they can help clinicians estimate how the ovaries may respond to stimulation.

There is an important distinction:

• A low AMH does not mean you cannot become pregnant.
• A reassuring AMH result does not guarantee that you will.

Ovarian reserve tests primarily tell us about egg quantity, not egg quality. Research has found that these tests are poor independent predictors of a woman’s natural reproductive potential. Age remains a much stronger predictor.

This is why an AMH test should not be treated as a simple “fertility test”.

Egg Quality: The Part Age Affects Most Significantly

Egg quality also changes with age. As eggs age, they become more likely to have abnormalities in their chromosomes. These are called aneuploidies. 

An embryo formed from an egg with a significant chromosomal abnormality may not implant successfully, may stop developing, or may result in miscarriage.

This is one of the major reasons fertility declines with age: it becomes not only harder to conceive, but also harder for a fertilised egg to develop into a healthy pregnancy.

The age-related increase in chromosomal abnormalities also helps explain why miscarriage becomes more common as maternal age increases. This is biological—not something a woman has caused through poor lifestyle choices.

What Happens In Your 20s, 30s and 40s?

There is no single age at which fertility changes for every woman. But understanding broad patterns can be useful.

From a biological perspective, reproductive ageing is gradual, cumulative and largely driven by ovarian biology rather than a sudden “switch”.

The ovary contains a finite pool of follicles established before birth, and both the quantity (ovarian reserve) and quality (chromosomal integrity of oocytes) decline over time. This decline is not linear—it tends to accelerate with age, particularly in the mid-to-late 30s.

Your 20s

For many women, fertility is relatively high during the 20s.

This is the period when:

• Ovarian reserve is generally at its highest
• Oocyte quality is, on average, optimal
• The proportion of chromosomally normal (euploid) eggs is highest
• Monthly fecundability (chance of conception per cycle) is at its peak

Population studies suggest that in healthy couples in their 20s, the chance of conception per menstrual cycle is often around 20–25%, assuming regular unprotected intercourse and no underlying fertility issues.

That does not mean every woman in her 20s will conceive easily. Conditions such as PCOS, endometriosis, previous pelvic infection, tubal disease and male-factor infertility can affect fertility at any age.

It is also important to note that “high fertility” does not mean “guaranteed fertility”—it simply reflects population-level biological probability.

Your early 30s

Fertility usually remains good in the early 30s, although a gradual decline has begun.

At a biological level, this is when we begin to see:

• A slow reduction in ovarian reserve (reflected in markers such as AMH and antral follicle count)
• A gradual increase in oocyte aneuploidy (chromosomal errors)
• Subtle reductions in cycle fecundability at a population level

Importantly, this decline is often not clinically obvious on an individual cycle-to-cycle basis, which is why many women in their early 30s conceive without difficulty.

This is also why fertility does not “suddenly drop at 35”—that threshold is a statistical simplification rather than a biological cliff edge.

For some women, this stage is when reproductive planning becomes more relevant, particularly if they are considering delaying pregnancy. From a clinical perspective, this is often the point where discussions about ovarian reserve testing or fertility preservation may be introduced in appropriate contexts.

Your Mid-to-Late 30s

The decline in fertility becomes more pronounced.

Large cohort studies consistently show:

• A measurable reduction in monthly fecundability from around age 35
• A more marked decline after 37–38
• Increasing time-to-pregnancy even in otherwise healthy couples

Biologically, this reflects two converging processes:

1. Reduced follicle quantity – fewer recruitable follicles per cycle
2. Reduced oocyte quality – higher rates of meiotic error leading to aneuploid embryos

As a result:

• The probability of conception per cycle decreases
• The risk of miscarriage increases (largely due to chromosomal abnormalities)
• The proportion of embryos that implant successfully declines

However, it is essential to emphasise that this is still a probabilistic shift, not a deterministic one.

Many women conceive naturally in their late 30s. The key change is that the distribution shifts: it may take longer, and the likelihood of needing more time or support increases.

From a clinical standpoint, this is also the period where fertility assessment becomes more time-sensitive if pregnancy is desired.

Your 40s

Pregnancy in the 40s is still possible, but fertility is significantly reduced at a population level.

By this stage:

• Ovarian reserve is typically low
• The proportion of euploid (chromosomally normal) eggs is substantially reduced
• Cycle fecundability declines further, often to low single-digit percentages per cycle in natural conception studies

In a contemporary preconception cohort, women aged 40–45 had around 60% lower fecundability per cycle compared with women aged 21–24 after adjustment for confounders.

The most important biological driver at this stage is oocyte aneuploidy, which increases sharply with age and is the primary reason for both reduced conception rates and increased miscarriage risk.

Fertility treatment can help some women conceive, particularly through IVF, 

It is important to understand that:

• IVF does not reverse oocyte ageing
• Success rates using a woman’s own eggs decline with age
• Donor eggs can bypass age-related egg quality decline because they come from younger ovaries

This is why reproductive medicine often frames the 40s as a period where time becomes a critical biological variable, and where earlier assessment and personalised counselling can be particularly valuable.

Beyond Your 40s

After 40, fertility continues to decline, and by the mid-to-late 40s, natural conception becomes uncommon, though not impossible.

By the late 40s:

• Ovulation becomes increasingly irregular and eventually ceases with menopause
• The remaining egg pool is extremely limited
• The likelihood of spontaneous pregnancy is very low, and miscarriage risk is high when conception does occur

Menopause typically occurs around age 51 on average, but the transition period (perimenopause) can begin several years earlier, during which cycle changes, hormonal fluctuations, and reduced fertility are common.

At this stage, reproductive care often shifts focus from prediction to support—helping women understand symptoms, manage perimenopausal changes, and explore options if pregnancy is still desired, including assisted reproduction or donor gametes where appropriate.

Importantly, the 40s and beyond are not only defined by decline, but also by clarity: for many women, this is the point at which reproductive goals become more defined, and medical guidance can help align expectations with biological reality and available options.

Your Family Fertility Timeline May Tell You Something Too

When thinking about fertility and age, most of us look at the calendar in front of us. 

However, it can also be useful to look backwards:

• When did your mother enter menopause? What about your grandmother? 
• If you have any – Did your sisters experience early or late menopause? 
• Did women in your family tend to have children relatively young, or did they conceive naturally later in life?

Your family reproductive history can provide useful context for your own reproductive health. This matters because fertility, menstrual health and menopause are not isolated events. There is a genetic component to the timing of reproductive ageing. 

Studies examining mothers and daughters have consistently shown a significant familial relationship in the age at natural menopause. Large population-based studies and twin research suggest that approximately 40–50% of the variation in menopausal age may be attributable to genetic factors, although estimates differ between populations and methodologies (Torgerson et al., 1997; de Bruin et al., 2001; Morris et al., 2011). 

The reproductive changes that eventually lead to menopause happen over many years. Fertility and fecundability can begin to decline before menopause itself occurs. In other words, the age at which a close female relative experienced reproductive ageing may provide one piece of information about your own reproductive timeline.

Your Mother’s Menopause May Be More Informative Than The Age She Had You

There is an important distinction here. If your mother had you at 39, that does not mean your body is programmed to remain highly fertile until 39. Likewise, if she had you at 25, it does not mean you will have difficulty conceiving after 30.

The age at which your mother became pregnant was influenced by many things—including when she chose to have children, her partner’s fertility, contraception, circumstances and chance. It is therefore not a reliable predictor of the age at which you will conceive. 

Her age at natural menopause, however, may provide more useful biological information.

Women whose mothers experienced early menopause are more likely to experience early menopause themselves. One large family study found that women were substantially more likely to experience early menopause when their mother or sister had also experienced early menopause (Treloar et al., 1998; Morris et al., 2011). 

This does not mean that your mother’s reproductive timeline determines yours. It means that family history can be one part of the picture.

What About Your Grandmother, Aunts and Sisters?

The pattern does not necessarily stop with your mother.

Reproductive aging can show familial patterns across generations, including among sisters and other close female relatives. Studies have found associations between the ages at which mothers, daughters and sisters experience natural menopause.

So, if you know that your mother entered menopause unusually early, your grandmother did too, or several close female relatives experienced early menopause, it is worth mentioning this to your gynaecologist.

It does not mean that you will definitely experience early fertility decline. However, it is a possibility. It may also be a reason to have a more informed conversation about your reproductive plans—particularly if you are considering delaying pregnancy for several years.

Think Of Your Family History As A Clue, Not A Countdown

This is where fertility conversations can easily become frightening. You might hear that your mother had her last period at 43 and immediately think:

“Does that mean I only have a few years left?” Not necessarily.

Family history cannot tell us exactly how many eggs you have, how healthy those eggs are, when you will ovulate for the last time or exactly when you will reach menopause.

There is also a substantial role for factors outside genetics, including smoking, certain medical treatments, body composition and other environmental influences. Even women from the same family can have very different reproductive experiences.

There is currently no test that can look at your family history and accurately predict the exact age at which you will stop being fertile.

Instead, think of family history as another piece of information alongside your age, menstrual history, medical history and reproductive goals. You do not need to turn your family history into a prediction. Instead, use it to start a conversation.

Your mother’s fertility story is not your fertility destiny—but it may contain useful clues about your reproductive history. When those clues are considered alongside your own health and reproductive goals, they can help you make decisions with more information and less uncertainty.

From The Consulting Room 

We often get asked a variety of questions regarding what affects fertility. One of the most useful fertility conversations we can have with women is not simply, “How old are you?” 

It is: “What do you want your reproductive future to look like?”

The following questions are ones we find particularly helpful in answering when having these conversations: 

What About The Age Of The Male Partner?

Fertility conversations often place almost all the focus on women. That isn’t quite fair—or biologically accurate.

Male fertility also changes with age. Semen parameters can decline, particularly later in reproductive life, and paternal age can influence reproductive outcomes. However, the relationship between age and fertility is generally much more pronounced in women, particularly because of changes in egg number and quality.

When a couple is struggling to conceive, both partners should therefore be assessed.

Infertility is not automatically a “woman’s problem”.

When Should You Consider A Fertility Assessment?

If you are trying to conceive, knowing when to seek help matters.

For women under 35, an infertility assessment is generally recommended after 12 months of regular unprotected intercourse without pregnancy, assuming there are no other concerning factors or underlying conditions.

For women aged 35 and older, assessment is generally recommended after six months of trying. For women over 40, earlier assessment may be appropriate rather than waiting six or twelve months.

You should also consider speaking to a healthcare professional sooner if you have:

• Irregular or absent periods
• Known or suspected PCOS
• Endometriosis
• Previous pelvic surgery
• Previous chemotherapy or radiation
• A history of pelvic inflammatory disease
• Previous ovarian surgery
• Recurrent pregnancy loss
• A known reproductive condition
• Concerns about ovarian reserve
• A partner with known or suspected fertility problems

The aim isn’t to assume something is wrong. It is to avoid losing valuable time when earlier investigation or treatment could make a difference.

Is Fertility Testing Worth Doing If I’m Not Trying To Conceive?

This is where fertility marketing can become confusing. You may see direct-to-consumer tests promising to tell you about your “fertility age” or how many years of fertility you have left.

Tests such as AMH can be clinically useful—but they should not be interpreted as a crystal ball.

AMH and other ovarian reserve markers can help estimate the number of follicles available and predict ovarian response during some fertility treatments. They do not reliably predict whether a woman will become pregnant naturally in the near future.

A woman can have a low AMH and conceive naturally. A woman can have a normal AMH and still experience infertility because of another factor. Your fertility is a whole picture—not a single blood test.

What About Freezing My Eggs?

Egg freezing, or oocyte cryopreservation, has given women another option when they want to preserve the possibility of using their own eggs in the future. It involves ovarian stimulation, egg retrieval and freezing the mature eggs for potential future use.

Egg freezing is not a guarantee of a future baby.

Age at the time the eggs are frozen is important because younger eggs are more likely to be chromosomally normal. The number of eggs retrieved, their maturity, survival after thawing, fertilisation and embryo development all influence the eventual chance of a live birth.

For this reason, egg freezing is best understood as fertility preservation, not fertility insurance.

If you are considering it, we can refer you to a fertility specialist who can discuss your age, ovarian reserve, reproductive plans and realistic expected outcomes rather than relying on a generic age-based promise.

Can Lifestyle Prevent Age-Related Fertility Decline?

Healthy lifestyle choices matter. Good nutrition, regular physical activity, avoiding smoking, moderating alcohol, maintaining a healthy weight and managing conditions such as diabetes or thyroid disease can support reproductive and overall health.

Healthy living cannot stop reproductive ageing. There is no supplement, detox, diet or fertility “hack” that can reliably preserve egg quality indefinitely. This is an important distinction because women are often made to feel responsible for fertility decline—as though the right diet or supplement could have prevented it.

Age-related changes in the ovaries are biological. They are not a personal failure. Your lifestyle can support the health you have, but it cannot change the fundamental biology of reproductive ageing.

The Maxima Takeaway

Your fertility is personal, but age is part of the picture.

There is no single age at which every woman becomes less fertile, and there is no test that can tell you exactly how many fertile years you have left. Fertility changes gradually, and the pace of that change can vary from one woman to another.

What we do know is that egg number and egg quality decline with age, particularly from the mid-30s onwards. Family history may offer additional clues about your reproductive ageing, while your menstrual health, medical history, lifestyle and reproductive goals add important context.

The most useful thing you can do is not panic about a number. It is to understand your own timeline.

If pregnancy is something you want now or in the future, knowing your options earlier can give you more choices. If you are trying to conceive and things are not happening as expected, seeking advice sooner can prevent valuable time from being lost.

If you are not ready for pregnancy, that is okay too. Fertility education isn’t about creating a countdown. It is about giving you enough information to make decisions that feel right for you.

At Maxima Women’s Health, we believe women deserve to understand their reproductive health before they are faced with a decision, a diagnosis or a deadline. Understanding your options early can help you get clarity in making decisions that are right for your body, your circumstances and your future.

Want to Understand Your Fertility Better?

Your reproductive health deserves more than a number on a calendar. Speak to us  at Maxima Women’s Health about your reproductive plans, fertility concerns or whether an assessment may be appropriate for you.

Trying to Conceive?

Knowing when to ask for help can prevent unnecessary waiting.

If you have been trying to conceive without success—or have a condition that may affect fertility—book a consultation with us at Maxima Women’s Health to discuss your individual circumstances.

Thinking About Pregnancy In The Future?

You don’t have to decide today, but having the right information can help you plan tomorrow. Talk to us at Maxima Women’s Health about your reproductive goals and whether fertility preservation or preconception counselling could be relevant to you.