Your fertility depends on several measurable factors, and there are both at-home methods and clinical tests that can give you a clearer picture. No single test gives a complete answer, but together they paint a reliable portrait of where you stand. Some signals you can track yourself starting today, while others require blood work through a doctor.
Track Your Cervical Mucus
The simplest way to gauge your fertility on any given day is to check your cervical mucus. It changes in predictable ways throughout your cycle, and those changes directly reflect how hospitable your body is to sperm at that moment.
Early in your cycle, after your period ends, mucus is thick, sticky, and dry, sometimes white or light yellow. This is a low-fertility window. As you approach ovulation, it shifts to a creamy, yogurt-like texture. Then, right before ovulation, it becomes wet, clear, and stretchy, closely resembling raw egg whites. This “egg white” stage is your most fertile window. Sperm can survive in this type of mucus for days, and it helps them travel toward the egg. After ovulation, the mucus returns to thick and dry.
To check, simply wipe before urinating or touch a small amount between your thumb and forefinger and see if it stretches. If it’s slippery and slimy, you’re likely in your fertile window. If it’s dry or pasty, you’re probably not.
Use Basal Body Temperature
Your resting body temperature shifts slightly after ovulation. By taking your temperature every morning before getting out of bed, you can confirm that ovulation happened. After ovulation, your temperature rises anywhere from 0.4°F to 1°F and stays elevated until your next period. You need a basal body thermometer (accurate to a tenth of a degree) and at least two to three months of charting to spot the pattern clearly.
The catch is that temperature rise tells you ovulation already occurred, so it’s more useful for confirming a pattern over several cycles than for pinpointing the exact day in real time. Combined with mucus tracking, though, it gives you a solid picture of whether you’re ovulating regularly and when your fertile window typically falls.
At-Home Ovulation Predictor Kits
Ovulation predictor kits (OPKs) detect a surge in luteinizing hormone (LH) in your urine. This surge is the trigger that tells your ovary to release an egg. Once LH rises in your blood, ovulation follows about 36 to 40 hours later. Because the hormone takes time to build up in urine, a positive test on a kit means ovulation is likely within 12 to 24 hours.
These kits are widely available at pharmacies and are straightforward to use. You test daily starting a few days before you expect to ovulate (typically around day 10 of a 28-day cycle). A positive result means you’re about to be at peak fertility. If you never get a positive result over several cycles, that’s worth discussing with a doctor, since it could indicate you’re not ovulating consistently.
Blood Tests That Measure Ovarian Reserve
If you want a deeper look at your fertility potential, particularly how many eggs you have left, blood tests can provide specific numbers. The most informative one is the anti-Müllerian hormone (AMH) test.
AMH is produced by the small follicles in your ovaries and reflects your ovarian reserve, essentially the size of your remaining egg supply. An average AMH level falls between 1.0 and 3.0 ng/mL. Below 1.0 is considered low, and 0.4 or below is severely low. To put those numbers in context, here’s roughly what AMH looks like by age:
- Age 25: around 3.0 ng/mL
- Age 30: around 2.5 ng/mL
- Age 35: around 1.5 ng/mL
- Age 40: around 1.0 ng/mL
- Age 45: around 0.5 ng/mL
These are estimates on the lower end of the range for each age. Your individual result could be higher. AMH can be drawn on any day of your cycle, which makes it convenient. It’s worth noting that AMH tells you about egg quantity, not egg quality. A normal AMH with poor egg quality (which increases with age) can still mean reduced chances of conception.
FSH and Progesterone
Follicle-stimulating hormone (FSH) is another key marker, tested on day 3 of your cycle. FSH is the hormone that tells your ovaries to develop an egg each month. When your ovarian reserve is declining, your body has to produce more FSH to get the same result, so a higher number is actually a worse sign. A level under 9 mIU/mL is considered normal with a good expected response to fertility treatment if needed. Between 9 and 11 is fair. Women in menopause typically have levels above 40.
Progesterone, tested around day 21 of your cycle, confirms whether ovulation actually took place. A level above 10 ng/mL indicates normal ovulation occurred. Below 10 suggests you either didn’t ovulate that cycle or the timing of the blood draw was off. If your progesterone is consistently low, it points to an ovulation problem that a fertility specialist can investigate further.
Age Is the Strongest Predictor
No matter what your test results show, age remains the single most powerful factor in fertility. A woman in her early to mid-20s has roughly a 25 to 30% chance of conceiving in any given month. That probability holds relatively steady through the late 20s, then begins a gradual decline in the early 30s that accelerates after 35. By age 40, the chance of conceiving in any monthly cycle drops to around 5%.
This decline is driven by two things happening simultaneously: you have fewer eggs, and the eggs you do have are more likely to carry chromosomal abnormalities. AMH and FSH can tell you about the first factor, but no blood test currently measures egg quality directly. Age is the best proxy we have for that.
Male Fertility Matters Too
Fertility is always a two-person equation. If you’re trying to conceive with a male partner, his sperm count, motility (how well sperm swim), and morphology (sperm shape) all play a role. A semen analysis is a simple test that evaluates all three. Male factors contribute to difficulty conceiving in roughly half of all couples who struggle, so it’s not something to overlook while focusing exclusively on the female side.
When Testing Makes Sense
If you’re under 35 and have been having regular, unprotected intercourse for 12 months without conceiving, that’s the standard point at which clinical evaluation is recommended. If you’re between 35 and 40, that timeline shortens to six months. If you’re over 40, or you have known risk factors like irregular periods, a history of pelvic infections, endometriosis, or prior ovarian surgery, evaluation can begin right away.
You don’t have to wait for those timelines to start tracking your own signs, though. Charting your cervical mucus, using OPKs, and monitoring your basal temperature can all give you useful information within a few cycles. If those home methods reveal that you’re not ovulating regularly, or if your cycles are very short, very long, or highly irregular, that’s meaningful information worth bringing to a doctor sooner rather than later.