About one in six people of reproductive age experience infertility at some point in their lives. The clearest sign is not becoming pregnant after a year of regular, unprotected sex, or after six months if you’re over 35. But many other signals from your body can hint at fertility problems well before you start trying to conceive. Some are obvious, like missed periods. Others are subtle, like changes in hair growth or a dip in sex drive. And in roughly 30% of infertile couples, standard testing reveals no identifiable cause at all.
Irregular or Absent Periods
For women, the most telling sign is a menstrual cycle that falls outside the normal range. A cycle shorter than 21 days, longer than 35 days, or one that skips months entirely often means you’re not ovulating regularly. No ovulation means no egg is available for fertilization. This can stem from hormonal imbalances, thyroid problems, being significantly under or overweight, or high levels of physical or emotional stress that disrupt the brain’s signals to the ovaries.
Completely absent periods (outside of pregnancy or menopause) are a stronger red flag. Even cycles that arrive on time but are extremely light or extremely heavy can indicate hormonal shifts that affect egg release or the uterine lining’s ability to support a pregnancy.
Pelvic Pain Beyond Normal Cramping
Most people experience some discomfort during their period. But pain that’s significantly worse than typical cramping, gets worse over the years, or radiates into your lower back deserves attention. This kind of pain is a hallmark of endometriosis, a condition where tissue similar to the uterine lining grows outside the uterus. Up to half of people with endometriosis have difficulty conceiving. The condition can physically block fallopian tubes and may also damage eggs or sperm in less direct ways.
Other pain patterns linked to endometriosis include pain during sex, and pain with bowel movements or urination that tends to flare around your period. Some people don’t discover they have endometriosis until they undergo fertility testing, because they assumed their pain level was normal. If pelvic pain interferes with your daily life or has been escalating, it’s worth investigating regardless of your plans around pregnancy.
Signs of Hormonal Imbalance in Women
Polycystic ovary syndrome (PCOS) is one of the most common causes of female infertility, and it often announces itself through visible changes. Excess hair growth on the chin, chest, upper thighs, or back is a classic sign, driven by higher-than-normal levels of androgens. You might also notice thinning hair on your scalp in a pattern similar to male baldness, or persistent acne that doesn’t respond to typical treatments.
Skin changes can also point to PCOS. Dark, velvety patches on the neck, armpits, or groin signal insulin resistance, which frequently accompanies the condition. Increased hunger and unexplained weight gain are other clues. PCOS symptoms tend to be more pronounced in people carrying extra weight, and obesity itself is a risk factor for developing the syndrome.
Another subtle sign is the absence of changes in cervical mucus throughout your cycle. Around ovulation, cervical mucus normally becomes clear, slippery, and stretchy. If you never notice this shift, it could indicate you’re not ovulating, even if you’re still getting a period.
Physical Signs in Men
Male factors contribute to roughly half of all infertility cases, yet men’s symptoms are often overlooked. The most straightforward physical sign is pain, swelling, or a lump in the testicle area. A varicocele, which is a swelling of the veins that drain the testicle, is the most common reversible cause of male infertility. It sometimes feels like a soft lump above the testicle or causes a dull ache that worsens throughout the day.
Testicle size matters too. Noticeably small or shrinking testicles can reflect hormonal problems or, in some cases, damage from anabolic steroid use. Steroids taken to build muscle can shrink the testicles and dramatically reduce sperm production, sometimes permanently.
Hormonal Red Flags in Men
Low testosterone doesn’t just affect muscle mass. It shows up as persistent fatigue, a noticeable drop in sex drive, and difficulty getting or maintaining erections. These symptoms overlap with many other conditions, which is part of why they’re easy to dismiss. But when several appear together, they often point to a hormonal environment that’s also hurting sperm quality.
Elevated estrogen levels in men can cause breast tenderness or visible enlargement of breast tissue. Mood changes, particularly feeling flat or irritable without a clear cause, may signal elevated prolactin, another hormone that can impair sperm production when it’s out of balance. None of these symptoms guarantee infertility on their own, but they’re signals worth investigating if you’re having trouble conceiving.
When There Are No Symptoms at All
One of the most frustrating realities of infertility is that it often comes with zero warning signs. Up to 30% of couples who undergo a full fertility workup receive a diagnosis of “unexplained infertility.” Their cycles are regular, hormone levels look normal, fallopian tubes are open, and semen analysis comes back within range. Everything checks out on paper, yet pregnancy doesn’t happen.
This is why the timeline itself is considered the primary diagnostic marker. If you’re under 35 and haven’t conceived after 12 months of trying, or over 35 and haven’t conceived after 6 months, that gap alone qualifies as a reason to start testing. If you’re over 40, guidelines recommend beginning evaluation right away rather than waiting.
What Testing Looks Like
For women, a fertility evaluation typically starts with blood tests to check hormone levels and an assessment of whether ovulation is occurring. One key blood test measures anti-Müllerian hormone (AMH), which estimates how many eggs remain in your ovaries. Average AMH falls between 1.0 and 3.0 ng/mL, but what’s considered normal shifts with age. At 30, a level around 2.5 ng/mL is expected. By 40, it drops to around 1.0 ng/mL. Levels below 1.0 at any age are considered low, and below 0.4 is severely low. A low result doesn’t mean pregnancy is impossible, but it does affect the urgency and approach to treatment.
Imaging tests check whether the fallopian tubes are open, and ultrasound can reveal structural issues like fibroids or ovarian cysts.
For men, the starting point is a semen analysis. This measures sperm count, movement, and shape, along with semen volume (normal is 1.5 to 7.6 milliliters) and pH. There’s no reliable way to assess sperm quality at home based on appearance alone. Semen that looks completely normal can still have low sperm counts or poor motility, which is why lab analysis is essential even when nothing seems off.
Signs That Deserve Early Attention
Some situations warrant evaluation before the standard 6- or 12-month timeline. If you’ve had two or more miscarriages, a history of sexually transmitted infections, prior cancer treatment, or surgery in the pelvic or abdominal area, these factors can independently affect fertility. The same goes for men with a history of undescended testicles, groin injuries, or known hormonal conditions.
Paying attention to the signals your body sends, from cycle irregularities and pain patterns to changes in sex drive and physical appearance, puts you in a better position to seek help early. Infertility is common, and many of its causes are treatable once identified.