Infertility is clinically defined by how long you’ve been trying to conceive without success: 12 months of regular, unprotected intercourse if the female partner is under 35, or 6 months if she’s 35 or older. About 8.5% of married women of reproductive age in the U.S. experience infertility, and that number jumps to 19.4% among women who have never given birth. But the inability to conceive isn’t the only signal. Several physical signs, lifestyle factors, and diagnostic tests can reveal fertility problems before or during the process of trying.
Menstrual Cycle Clues for Women
Your menstrual cycle is one of the most accessible windows into your fertility. A cycle shorter than 21 days, longer than 35 days, or one that’s consistently irregular can mean you’re not ovulating. In some cases, periods stop entirely. These patterns don’t guarantee infertility, but they point to hormonal or structural issues worth investigating. Many women with fertility problems have no other symptoms at all besides difficulty conceiving.
Polycystic ovary syndrome (PCOS) is one of the most common causes of irregular ovulation. It creates a hormone imbalance that can show up as unusual hair growth on the face or body, persistent acne, weight gain, and missed or unpredictable periods. Endometriosis, another frequent contributor, often causes painful periods and pelvic pain, sometimes along with pain during sex. A history of pelvic inflammatory disease, repeated miscarriages, or sexually transmitted infections also raises the likelihood of fertility problems and is reason enough to seek evaluation sooner rather than later.
Physical Signs in Men
Male factors contribute to roughly half of all infertility cases, yet many men assume the issue lies elsewhere. The physical signs are often subtle. A varicocele, which is an enlarged vein in the scrotum, is one of the most common treatable causes of male infertility. It can cause a dull ache that worsens throughout the day, one testicle that’s noticeably smaller than the other, or a visible mass above the testicle that feels like a “bag of worms.” Not all varicoceles cause infertility, but they can lead to low sperm production and poor sperm development.
Difficulty with ejaculation, low sexual desire, or erectile problems can also signal hormonal issues that affect fertility. Pain or swelling in the testicles deserves medical attention regardless of whether you’re trying to conceive.
How Age Affects Your Chances
Age is the single most predictive factor in female fertility. A woman in her early to mid-20s has a 25 to 30% chance of getting pregnant in any given month. That probability starts declining in the early 30s, accelerates after 35, and drops to around 5% per cycle by age 40. This decline happens because both the number and quality of eggs decrease over time, a process that’s impossible to reverse.
Male fertility also declines with age, though more gradually. Sperm quality, including motility and DNA integrity, tends to decrease after the mid-40s.
What You Can Track at Home
Several at-home methods can help you identify whether you’re ovulating, which is a key piece of the fertility puzzle. Ovulation predictor kits detect a surge in a hormone that triggers egg release, and they’re widely available at pharmacies. Cervical mucus monitoring looks for changes in discharge that correlate with peak fertility, specifically a clear, stretchy consistency similar to egg whites.
Basal body temperature tracking, where you take your temperature every morning before getting out of bed, is the least reliable option. Your temperature rises by about 0.5 to 1.0°F shortly after ovulation, but a 2017 study found this method was only about 22% accurate in detecting ovulation. The rise also confirms ovulation after it’s already happened, making it less useful for timing intercourse in a given cycle. If you want a more reliable picture, combining methods or using ovulation predictor kits gives better results.
Lifestyle Factors That Lower Fertility
Certain habits directly affect your ability to conceive. Smoking is linked to lower sperm counts in men and reduced egg quality in women. A BMI over 30 is associated with decreased sperm count and sperm movement, and in women, excess weight disrupts ovulation. Excessive heat exposure to the scrotum, from hot tubs, laptops, or prolonged sitting, may reduce sperm production. None of these factors make conception impossible on their own, but they stack the odds against you.
Diagnostic Tests for Women
When it’s time for medical evaluation, doctors typically start with blood work to measure hormones that reflect ovarian function. Two key markers are FSH (follicle-stimulating hormone) and AMH (anti-Müllerian hormone). FSH levels above 10 IU/L, measured early in your cycle, can suggest diminished ovarian reserve, meaning fewer eggs remain. AMH levels below 0.7 ng/mL are considered low, and extremely low levels (below 0.16 ng/mL) are associated with significantly reduced success in fertility treatments, with a live birth rate of only about 9.5% per treatment cycle.
That said, these numbers aren’t destiny for natural conception. Research from the EAGER trial found that women with low AMH had similar cumulative pregnancy rates to women with normal levels when trying to conceive naturally. The tests are better at predicting how well you’d respond to fertility treatments than at predicting whether you can get pregnant on your own.
A hysterosalpingogram, or HSG, is an imaging test that checks whether your fallopian tubes are open and whether your uterus has a normal shape. A doctor inserts contrast dye into the uterus and takes X-rays. If the dye flows freely through the tubes and spills out the ends, they’re clear. If it meets a barrier, there’s a blockage. Blocked tubes can result from endometriosis, prior ectopic pregnancy, infections, or scar tissue. The HSG can also detect structural uterine variations, fibroids, and polyps that may interfere with implantation.
Diagnostic Tests for Men
A semen analysis is the standard first test for male fertility. It measures three main things: sperm count, motility (how well sperm move), and morphology (whether sperm are normally shaped). The World Health Organization’s reference values set the bar at 39 million sperm per ejaculate, at least 32% actively moving forward, and more than 4% with normal shape. Falling below these thresholds doesn’t mean you can’t father a child, but it does indicate reduced fertility and usually prompts further investigation.
The test requires providing a sample after two to five days of abstinence. Results can vary from one sample to the next, so doctors often repeat the analysis before drawing conclusions. If results are abnormal, follow-up may include hormone testing, ultrasound of the scrotum, or genetic screening depending on the severity.
When Evaluation Should Happen Sooner
The 6- or 12-month timelines are general guidelines for couples without known risk factors. Evaluation should start earlier if you have irregular or absent periods, a history of pelvic inflammatory disease or sexually transmitted infections, known endometriosis, prior cancer treatment, or repeated miscarriages. For men, a history of testicular injury, surgery, or known hormonal issues also warrants earlier testing. About 13.7% of U.S. women ages 20 to 49 have used some form of fertility services, so seeking help is far more common than most people realize.