Age and fertility

How does age actually affect fertility?

Fertility naturally declines with age for both partners, though the timing and pace differ. For women, the decline becomes noticeable in the early-to-mid 30s and speeds up after 35, driven mainly by a drop in the number and quality of eggs remaining in the ovaries. For men, sperm quality also declines with age, though more gradually and later, typically becoming a measurable factor from the mid-40s onward. Age doesn't make pregnancy impossible at any of these stages — it changes the odds and the average time it takes.

The underlying biology is that you're born with all the eggs you'll ever have, and that supply steadily shrinks and ages over your reproductive years. Egg quality — the likelihood a given egg has the right number of chromosomes — declines alongside quantity, which is part of why the risk of miscarriage and certain chromosomal conditions rises with age too. Sperm, by contrast, are produced continuously throughout life, so male fertility declines more slowly and more variably from person to person. None of this means age alone determines whether or when you'll conceive.

What actually changes for women as they get older?

For women, the biggest age-related changes are a lower chance of conceiving in any given cycle, a longer average time to pregnancy, and a higher chance of pregnancy loss, all becoming more noticeable from the mid-30s and more pronounced after 40. Ovulation can also become less predictable as you approach perimenopause, even while periods are still regular. Ovarian reserve — the number of eggs remaining — can be estimated with blood tests like AMH, though these predict egg quantity rather than egg quality, and can't say exactly when your fertility will decline. These are trends seen across large groups of people, not a fixed timeline for any one individual, and many people conceive without difficulty well into their late 30s and 40s.

Age also affects pregnancy itself, not just conception. The chance of miscarriage and of chromosomal conditions such as Down syndrome rises gradually with maternal age, becoming more noticeable from the mid-30s onward — this is part of why screening tests like NIPT are offered earlier or more strongly recommended as you get older. Pregnancies after 35 are also watched more closely for conditions like gestational diabetes and high blood pressure, simply because the statistical risk is higher, not because something is presumed to be wrong. None of this predicts what will happen in your specific pregnancy — it's the reason for closer monitoring, not a diagnosis in itself.

Does male age affect fertility too?

Yes — sperm quality and count both decline with age, though the change is slower and more gradual than the female pattern, and there's no clear cutoff age where male fertility drops sharply. From around the mid-40s, many providers see measurable declines in sperm motility (how well sperm move) and morphology (their shape), along with a modest rise in DNA fragmentation. Older paternal age has also been linked to a small increase in certain genetic conditions in offspring. Male fertility doesn't disappear with age, but it isn't unaffected by it either.

Lifestyle and health factors often matter as much as age for sperm quality — smoking, heavy alcohol use, obesity, certain medications, and prolonged heat exposure (like frequent hot tub use) can all lower sperm counts and motility at any age. A standard semen analysis is a simple, inexpensive way to check count, motility, and morphology, and it's usually one of the first tests offered when a couple starts a fertility evaluation. If you're an older father-to-be and have concerns, raising them with your doctor is reasonable — it doesn't need to wait until you've been trying for months.

What are the actual chances of getting pregnant at different ages?

Averaged across large groups, the monthly chance of conceiving is highest in your 20s, declines gradually through your early 30s, more noticeably from the mid-30s, and drops more steeply after 40. These are population averages, not individual predictions — plenty of people conceive quickly in their late 30s or 40s, and plenty of people in their 20s take longer than expected. The table below shows the general pattern doctors describe when discussing age and fertility. It's most useful for understanding why the standard advice about when to seek help gets more cautious as you get older, not as a forecast for your own body.

| Age range | General fertility pattern | Miscarriage risk (relative) | Typical time-to-seek-help threshold | |---|---|---|---| | Under 30 | Near the highest of the reproductive years | Lower | About 12 months of trying | | 30–34 | Gradually declining, still relatively high | Slightly higher | About 12 months of trying | | 35–39 | More noticeable decline | Higher | About 6 months of trying | | 40 and over | Significantly lower | Meaningfully higher | Often right away, or after a few months |

When both partners are older, these effects can add up rather than simply average out, which is one reason some clinics ask about both partners' ages at the very first visit. A couple where one partner is over 35 and the other is over 40 may be advised to seek evaluation sooner than either age alone would suggest. None of this means conception won't happen naturally — it means the odds shift, and getting a baseline check earlier costs little and can catch a treatable issue sooner rather than later.

When should you seek help based on age?

The standard guidance is to seek a fertility evaluation after 12 months of trying without success if you're under 35, or after 6 months if you're 35 or older, because the statistical chance of an undiagnosed issue climbs enough by then to make investigating worthwhile. If you're over 40, many providers suggest seeking evaluation right away rather than waiting even a few months. Our guide to [fertility evaluation](/getting-pregnant/fertility-evaluation) walks through what that first visit and initial testing actually involve. These thresholds are guidelines, not strict rules, and your own history can shift them earlier.

Certain factors are reasons to seek evaluation sooner, whatever your age: irregular or absent periods, a history of pelvic infection or surgery, endometriosis, PCOS, two or more prior miscarriages, or a partner with known fertility concerns. If you notice increasingly irregular cycles, hot flashes, or other signs that might suggest perimenopause while you're still trying to conceive, mention this to your provider without delay — earlier information gives more options. Waiting rarely helps in these situations, and there's no advantage to letting months pass before asking questions you already have.

What can you do if you're trying to conceive at an older age?

Track your cycle and time intercourse around your fertile window, get a baseline fertility check earlier rather than later, and address modifiable factors like smoking, weight, and alcohol for both partners, since these affect fertility at every age. If you're 35 or older, don't wait the full year before asking your doctor for basic testing — a semen analysis, ovarian reserve testing, and a check of ovulation can usually be arranged quickly and give useful information early. None of these steps guarantee a particular outcome, but they narrow down what, if anything, is making things harder.

Tools like babybumpkit's [ovulation calculator](/ovulation-calculator) or [conception calculator](/conception-calculator) can help you use your fertile days as effectively as possible while you decide on next steps. If initial testing finds an issue, treatments ranging from ovulation-inducing medication to IUI or IVF are available and often effective, and age affects success rates for these too, which your provider can walk you through in detail. If you're already anxious about your age and fertility, that worry is common and worth naming to your provider directly — they can tell you what's realistic for your specific situation, which a general article like this one cannot.

Frequently asked questions