You can get a good sense of your fertility by paying attention to a few signals your body sends each month, particularly changes in cervical mucus, subtle shifts in body temperature, and the regularity of your menstrual cycle. These signs tell you whether and when you’re ovulating, which is the core question behind fertility. Beyond day-to-day tracking, blood tests and imaging can give you a more complete picture if you need one.
Your Cervical Mucus Is the Strongest Daily Clue
The discharge your cervix produces changes throughout your cycle in predictable ways, and learning to read those changes is one of the most reliable free methods for spotting your fertile window. In the days right after your period, discharge is dry or tacky and usually white or slightly yellow. As you move toward the middle of your cycle, it becomes creamy and cloudy, similar to yogurt. Then, around days 10 to 14 of a typical 28-day cycle, it shifts dramatically: wet, stretchy, slippery, and clear, closely resembling raw egg whites.
That egg-white stage is your most fertile window. It lasts roughly three to four days and creates an environment that helps sperm survive and travel. The rule is simple: if your mucus is dry or sticky, you’re likely not fertile yet. If it’s wet, slippery, or slimy, you probably are. After ovulation, discharge dries up again and stays that way until your next period.
Ovulation Predictor Kits and the LH Surge
Home ovulation test strips detect a hormone called LH in your urine. Your body releases a surge of LH right before ovulation, and once that surge shows up on a test strip, you can expect to ovulate within 12 to 24 hours. These kits are up to 99% effective at identifying your most fertile days, making them a popular choice if you want confirmation beyond mucus tracking alone.
The actual release of the egg happens about 36 to 40 hours after LH levels spike in your blood, but because it takes time for the hormone to build up in urine, the window between a positive strip and ovulation is shorter. Most people test once or twice daily starting a few days before they expect to ovulate. If your cycles are irregular, you may need to test over a longer stretch.
Basal Body Temperature Tracking
Your resting body temperature rises slightly after you ovulate, typically less than half a degree Fahrenheit (about 0.3°C). The shift is small enough that you need a thermometer accurate to one-tenth of a degree, and you need to take your temperature at the same time each morning before getting out of bed.
The catch with this method is that it confirms ovulation after the fact. You’ll see a sustained temperature rise for several days following the egg’s release, which tells you ovulation already happened. Over a few months of charting, patterns emerge that help you predict when the rise is coming. On its own, temperature tracking works best in combination with mucus observation so you’re not relying on hindsight alone.
Physical Symptoms Around Ovulation
Up to 40% of people who ovulate experience a sensation called ovulation pain, a mild twinge or sometimes a sudden sharp ache on one side of the lower abdomen. It happens on whichever side is releasing the egg that month. Some people feel it for just a few minutes, others for most of the day. It can come with light vaginal spotting, low back pain, or nausea if the discomfort is significant.
Breast tenderness, a heightened sense of smell, and increased sex drive are other secondary signals some people notice around ovulation. None of these are reliable enough on their own to confirm fertility, but when they line up with mucus changes or a positive ovulation strip, they add confidence that your body is doing what it should.
What a Regular Cycle Tells You
A menstrual cycle anywhere from 21 to 35 days is considered normal. If your periods arrive on a roughly predictable schedule within that range, it’s a strong sign that you’re ovulating regularly. Ovulation typically happens about 14 days before your next period starts, not 14 days after your last one. So in a 28-day cycle, ovulation falls around day 14, but in a 35-day cycle, it’s closer to day 21.
Cycles that are consistently very short, very long, or wildly unpredictable can signal that ovulation is happening infrequently or not at all. Skipped periods, cycles shorter than 21 days, or cycles longer than 35 days are worth discussing with a healthcare provider because they may point to hormonal imbalances that affect fertility.
How Age Affects Your Odds
Even with perfect ovulation, age plays a major role in the probability of conception each month. In your early to mid-20s, the chance of getting pregnant in any given cycle is about 25 to 30%. That probability declines gradually through your 30s and drops more sharply after 35. By age 40, the odds fall to around 5% per cycle.
This decline is tied to both egg quantity and egg quality. A blood test measuring a hormone called AMH (anti-Müllerian hormone) can estimate how many eggs you have left. AMH levels peak around age 25 and drop steadily from there. General benchmarks: around 3.0 ng/mL at 25, about 2.5 at 30, roughly 1.5 at 35, near 1.0 at 40, and approximately 0.5 at 45. Levels below 1.0 are considered low. An AMH test doesn’t measure egg quality, but it gives you a useful snapshot of your ovarian reserve.
Medical Tests That Go Deeper
If you’ve been tracking signs of ovulation and haven’t conceived after several months of trying (or if something seems off with your cycle), clinical testing can identify issues that home tracking can’t. For women, this often starts with blood work to check hormone levels, including AMH, thyroid hormones, and progesterone to confirm that ovulation is actually occurring.
A procedure called an HSG (hysterosalpingography) can check whether your fallopian tubes are open. During the test, dye is passed through the uterus and tubes while X-ray images are taken. If the dye flows freely, the tubes are clear. If a tube is blocked, the dye causes it to stretch visibly on the image. The test also reveals abnormalities in the shape or lining of the uterus that could interfere with implantation.
Male Fertility Signs
Fertility isn’t only a female concern. Roughly half of couples who struggle to conceive have a male factor involved. Unlike women, men don’t have obvious monthly signals to track, so male fertility is primarily assessed through a semen analysis. The test evaluates three main things: how many sperm are present, how well they move, and what percentage have a normal shape.
Current reference points consider a sperm concentration of at least 16 million per milliliter normal, with at least 42% of sperm showing some movement and at least 30% swimming forward effectively. Only about 4% of sperm need to have a normal shape to meet the threshold. Results below these numbers don’t necessarily mean conception is impossible, but they do lower the probability and may call for further evaluation. Factors like heat exposure, smoking, heavy alcohol use, and certain medications can all affect sperm quality, and many of those are reversible.