If you’ve been having regular, unprotected sex for 12 months without getting pregnant, that’s the standard threshold doctors use to evaluate fertility. For women over 35, that window shortens to six months. But there are also physical signs, cycle patterns, and risk factors that can signal a problem well before you hit those timelines.
How Long Is Normal?
Even when everything is working perfectly, the odds of conceiving in any single month are lower than most people expect. A woman in her early to mid-20s has roughly a 25 to 30 percent chance of getting pregnant each cycle. By 40, that drops to about 5 percent per cycle. So several months of trying without success doesn’t necessarily mean something is wrong. It means the math is playing out normally.
The clinical definition of infertility is 12 months of unprotected sex without a successful pregnancy. If you’re older than 35, the recommendation is to seek evaluation after just six months. And if you already suspect an underlying issue, like very irregular periods or a known medical condition, there’s no reason to wait at all.
What Your Period Can Tell You
Your menstrual cycle is one of the clearest windows into your reproductive health. A normal cycle falls between 21 and 35 days, with bleeding lasting two to seven days. Cycles that consistently fall outside that range, or that vary wildly from month to month, can indicate you’re not ovulating regularly. Without ovulation, pregnancy can’t happen.
Other patterns worth paying attention to: bleeding that lasts longer than seven days, soaking through more than one pad or tampon every hour or two, spotting between periods, or periods that stop entirely for stretches. None of these guarantee a fertility problem, but they all suggest hormonal imbalances that can interfere with conception. Tracking your cycle length for a few months gives you useful information to bring to a doctor if you decide to get evaluated.
Signs of PCOS and Endometriosis
Two of the most common conditions behind female infertility come with their own physical clues. Polycystic ovary syndrome (PCOS) often shows up around the time periods first start and includes irregular or missed periods, excess hair growth on the face and chin, persistent acne or oily skin, weight gain or difficulty losing weight, thinning hair on the head, and darkened skin around the neck or body folds. PCOS disrupts ovulation, which is why it’s so closely linked to difficulty conceiving.
Endometriosis looks different. Its hallmark is severe pelvic or lower-back pain, usually during menstruation, though it can also cause heavy or irregular bleeding, pain during sex, painful bowel movements or urination, chronic fatigue, and nausea. Endometriosis involves tissue similar to the uterine lining growing outside the uterus, which can damage the fallopian tubes and ovaries over time. If you recognize a cluster of these symptoms in yourself, they’re worth bringing up with a provider regardless of how long you’ve been trying to conceive.
Male Fertility Red Flags
Fertility problems aren’t only a female issue. Male factors contribute to roughly half of all cases where couples struggle to conceive, and some of those have visible or noticeable signs. Difficulty maintaining an erection, problems with ejaculation, low sex drive, or unusually small volumes of ejaculate can all point to an underlying issue. Pain, swelling, or a lump in the testicle area is another signal.
Some less obvious signs include reduced facial or body hair, abnormal breast tissue growth, and recurrent respiratory infections paired with an inability to smell (which can indicate a rare genetic condition affecting hormone production). A history of testicular injury, groin surgery, or prostate problems also raises the risk. A normal sperm count is at least 15 million sperm per milliliter. A semen analysis is typically the first test a doctor orders when evaluating male fertility, and it’s straightforward to do.
Lifestyle Factors That Shift the Odds
Smoking has a well-documented effect on fertility. Women who smoke are 54 percent more likely to experience a delay of over 12 months in conceiving compared to nonsmokers, and the effect gets worse with the number of cigarettes smoked per day. This applies to both natural conception and assisted reproduction. Smoking also affects sperm quality in men.
Body weight matters too. Being significantly underweight or overweight can disrupt the hormonal signals that drive ovulation. While the exact numbers vary, doctors consistently flag BMI as a factor worth addressing when couples are having trouble conceiving. Alcohol use, high stress levels, and exposure to certain environmental chemicals (like those found in some pesticides and industrial solvents) can also play a role, though their effects are harder to quantify individually.
What Fertility Testing Looks Like
If you do decide to get evaluated, the process typically starts with blood tests and imaging. For women, doctors measure two key hormones. Follicle-stimulating hormone (FSH) is tested around day three of your cycle and reflects how hard your body is working to trigger ovulation. Higher levels can suggest a declining egg supply. Anti-mullerian hormone (AMH) can be measured at any point in your cycle and gives a snapshot of your remaining egg reserve. Levels below 1 nanogram per milliliter may indicate that supply is declining, though a low AMH alone doesn’t predict whether you can or can’t get pregnant.
Doctors also use a transvaginal ultrasound to count the small follicles visible in your ovaries, usually within the first four days of your cycle. This antral follicle count, combined with hormone levels, paints a more complete picture of your ovarian reserve. Additional tests can check whether your fallopian tubes are open and whether the uterine cavity looks normal. For men, a semen analysis measures sperm count, movement, and shape. Together, these tests can often pinpoint where the problem lies or confirm that everything looks fine and more time may be all that’s needed.
When Age Becomes the Main Factor
Age affects fertility more steeply than most people realize, and the decline isn’t gradual. Women are born with all the eggs they’ll ever have, and both the number and quality of those eggs drop over time. The sharpest decline begins in the mid-30s and accelerates after 37. By 40, the monthly chance of conception is about a fifth of what it was at 25. This isn’t just about egg quantity. Older eggs are more likely to have chromosomal abnormalities, which increases the risk of miscarriage and makes each cycle less likely to result in a viable pregnancy.
Male fertility also declines with age, though more gradually. Sperm quality, including motility and DNA integrity, decreases over time. Men over 40 tend to take longer to conceive with a partner even when the partner is younger. Age on both sides of the equation matters, and it’s the one factor you can’t modify, which is why the timelines for seeking evaluation are shorter for older individuals.