Infertility means that pregnancy has not occurred after a period of regular attempts, or that a person’s reproductive capacity is impaired by a known condition. It can involve ovulation, eggs, sperm, fallopian tubes, the uterus, sexual function, or several factors together; sometimes no cause is found. A useful evaluation looks at all relevant contributors in parallel and matches the pace to age, history, and goals.
Key points
- Common guidance starts evaluation after about 12 months of regular unprotected sex when the egg-producing partner is under 35, and after about 6 months from 35; earlier assessment is appropriate with known risks or older reproductive age.
- These time points are clinical guides, not a judgment about who deserves care, and local definitions and eligibility rules differ.
- When pregnancy involves eggs and sperm from two partners, evaluate both at the same time rather than completing one person’s tests first.
- Initial assessment focuses on ovulation, reproductive anatomy and tubal patency, and semen; not every hormone, immune, genetic, or surgical test is routine.
- Treatment depends on cause, age, duration, safety, preferences, access, and whether the goal is pregnancy now or fertility preservation.
What infertility means
The World Health Organization defines infertility as a disease of the reproductive system involving failure to achieve pregnancy after 12 months or more of regular unprotected sexual intercourse. This definition supports public-health measurement and access to care, but it does not require every person to wait exactly 12 months before asking a question or receiving assessment.
People seek fertility care in many circumstances: a different-sex couple trying through intercourse, a single person or same-sex couple using donor sperm or eggs, someone with a known reproductive condition, a person planning treatment that may damage fertility, or a transgender person considering preservation before medical or surgical care. NICE’s 2026 guideline applies regardless of sexual orientation, partnership status, or gender identity.
Infertility is not the same as sterility. Many people with reduced fertility conceive without treatment or with assistance, but no test or treatment can promise an individual pregnancy or live birth. The term “subfertility” is sometimes used to emphasize reduced probability rather than impossibility.
When to seek an evaluation
In common US guidance, people with no known risk often begin evaluation after 12 months when the partner providing eggs is younger than 35, after 6 months from age 35, and more promptly over 40. Other countries use different age bands, intervals, and access rules. Age matters because egg number and quality decline over time, while the pace and degree vary among individuals.
Do not delay when periods are absent or very irregular, cycles are unusually short, severe menstrual or pelvic pain suggests endometriosis, or there is known tubal or uterine disease. Earlier review is also appropriate after pelvic inflammatory disease, ectopic pregnancy, repeated pregnancy loss, ovarian or testicular surgery, testicular injury or undescended testes, chemotherapy or radiation, genetic risk, sexual dysfunction, or a previous fertility problem.
Preconception care can happen before attempts begin. A clinician can review medicines, vaccinations, chronic disease, occupational exposures, genetic carrier questions, nutrition, and the timing of treatment that may affect eggs or sperm. Asking early does not commit someone to assisted reproduction.
Pregnancy requires several steps
An ovary must develop and release an egg. Sperm must be produced, transported, and delivered at the appropriate time. Egg and sperm must meet, usually in a fallopian tube. The resulting embryo must travel to the uterus, attach to a receptive lining, and continue developing. A problem at any step can reduce the chance per cycle.
Timing intercourse or insemination near ovulation matters, but an app predicts rather than confirms ovulation. Cycle length can vary, and sperm can survive longer than an egg remains fertilizable. Rigid schedules can increase stress and do not overcome a blocked tube, absent ovulation, or a major sperm-production problem.
Ovulation and ovarian factors
Polycystic ovary syndrome is a common cause of irregular or absent ovulation. Thyroid or pituitary disorders, high prolactin, primary ovarian insufficiency, extremes of energy availability, major weight change, intense exercise, stress, and some medicines can also disrupt cycles. Regular cycles often—but not always—suggest ovulation.
Ovarian reserve describes the remaining pool of recruitable eggs, not egg quality or the certainty of natural conception. Age remains central. Measures such as anti-Müllerian hormone, antral follicle count, and selected cycle-timed hormones can help plan treatment response, but ASRM cautions that ovarian-reserve tests are poor stand-alone predictors of fertility and should not be used as universal screening.
Primary ovarian insufficiency can occur before age 40 and may cause irregular periods, hot flushes, vaginal symptoms, or infertility. It requires broader health assessment, not only a fertility plan.
Fallopian tubes, uterus, and pelvic conditions
Fallopian tubes may be blocked or damaged after pelvic infection, endometriosis, ectopic pregnancy, or surgery. Some people have no symptoms. Tests that use contrast with X-ray or ultrasound can assess whether fluid passes through the tubes, though results and discomfort need interpretation.
Fibroids, polyps, adhesions, or congenital differences in the uterine cavity can affect implantation or pregnancy depending on location and size. A routine pelvic ultrasound shows the uterus and ovaries; saline imaging, X-ray contrast, hysteroscopy, or other procedures are selected when the initial picture or history indicates them.
Endometriosis can cause severe menstrual pain, pain with sex, bowel or bladder symptoms, or infertility, but symptoms do not reliably show extent. Laparoscopy is not a routine first test for every infertility evaluation; it is used when the expected diagnostic or treatment value justifies surgery.
Sperm and male reproductive factors
Sperm-related infertility can involve production, movement, shape, transport, ejaculation, erection, hormones, or genetic factors. Contributors include varicocele, testicular injury or infection, undescended testes, blockage, cancer treatment, some medicines, anabolic testosterone exposure, chronic disease, heat or toxin exposure, and inherited conditions.
A semen analysis measures volume and selected sperm characteristics, commonly concentration, movement, and shape. Results vary between samples and laboratories. A result outside a reference range does not by itself prove infertility, and a result within range does not guarantee conception. Repeat testing and specialist interpretation may be needed.
External testosterone can suppress the hormones that drive sperm production. Anyone trying to conceive or preserve fertility should tell the prescriber before starting or continuing hormone treatment. Do not stop it abruptly without an individualized plan.
See Male Infertility and Sperm Health for a detailed explanation of semen testing and next steps.
Unexplained infertility is a real diagnosis of exclusion
Sometimes ovulation appears to occur, at least one tube is open, the uterine cavity is suitable, and semen analysis does not reveal a sufficient explanation, yet pregnancy has not occurred. This is called unexplained infertility. It does not mean nothing is wrong or that the problem is psychological; current tests cannot measure every step of egg, sperm, fertilization, embryo development, and implantation.
Duration, age, previous pregnancy, test results, and preferences guide the next step. Repeating low-value tests indefinitely may not improve decisions.
What happens at the first visits
The history covers duration and timing of attempts, previous pregnancies and losses, cycle pattern, pelvic symptoms, sexual function, infections, operations, cancer treatment, chronic disease, medicines, supplements, family history, work exposures, smoking, alcohol, drugs, and reproductive goals. Relevant partners should be assessed in parallel when their eggs or sperm are involved.
Physical examination is targeted. It may include blood pressure, signs of hormone imbalance, pelvic examination or ultrasound, and examination of testes, penis, or secondary sexual features. Not everyone needs every component at the first visit.
Initial tests often address ovulation, anatomy and tubal patency, and semen. Thyroid and other hormone tests are ordered according to cycle pattern and symptoms. Genetic testing is used when history or findings suggest a condition, not as a universal package. Postcoital tests, broad immune panels, thrombophilia testing, endometrial biopsy, advanced sperm-function tests, and diagnostic surgery are not routine without specific indications.
Understanding fertility-test limits
A test result changes probability; it rarely labels someone fertile or infertile on its own. Reference ranges are built from populations and do not incorporate every factor in a couple or individual. Home hormone and sperm tests may provide a limited measure but cannot assess tubes, uterine anatomy, egg quality, sexual function, genetics, or the full semen profile.
Ask what question a test answers, how it will change treatment, whether it must be timed within a cycle, and what false reassurance or false alarm is possible. Request copies of reports and note units because methods differ.
Treatment pathways
Treatment begins with the identified cause where possible. Options may include support for timed intercourse or insemination, treatment to restore ovulation, surgery for selected anatomic problems, sperm retrieval, intrauterine insemination, or assisted reproductive technology such as in vitro fertilization. Donor sperm, eggs, or embryos and gestational-carrier pathways are options in some settings.
The choice depends on age, diagnosis, duration, previous treatment, pregnancy safety, likelihood of live birth, risk of multiple pregnancy, burden, cost, access, values, and local law. More intensive treatment is not automatically better. WHO’s 2025 guideline emphasizes evidence-based care and reducing inequity, while national rules determine what is available.
Success rates must be interpreted carefully. Per-cycle, per-transfer, per-retrieval, cumulative pregnancy, and live-birth rates answer different questions. Clinic comparisons can be distorted by which patients are accepted and how outcomes are reported. An individual estimate should explain its assumptions and uncertainty.
Fertility preservation
Freezing sperm, eggs, embryos, or reproductive tissue may be discussed before chemotherapy, pelvic radiation, ovary or testis removal, and selected medical or gender-affirming treatments. Time can be limited, so early referral is important. Preservation stores reproductive material; it does not guarantee a future pregnancy.
People considering age-related elective preservation should receive realistic information about age at freezing, likely number of procedures, storage, future use, cost, and legal disposition. Marketing should not describe freezing as an insurance policy.
Health habits without blame
Smoking, heavy alcohol use, anabolic steroids, recreational drugs, severe nutritional restriction, and selected workplace or heat exposures can affect reproductive health. Balanced nutrition, appropriate activity, sleep, and management of chronic conditions support pregnancy preparation but cannot correct every fertility factor.
Do not begin a large supplement stack. Excess nutrients and unregulated products can cause harm or interact with treatment. A preconception folate plan and other supplements should follow the needs of the person who may become pregnant and local guidance.
Emotional and practical support
Uncertainty, repeated testing, pregnancy announcements, sex scheduled around treatment, cost, and loss can affect mood and relationships. Support may come from a fertility counselor, mental-health professional, peer group, faith or community resource, or clinic social worker. Psychological support improves coping; it is not a claim that stress caused infertility.
Discuss boundaries for appointments, family questions, work, and treatment decisions. Partners may process uncertainty differently. Single people and LGBTQ+ families may face additional legal, financial, or discriminatory barriers that the care team should address directly.
When symptoms are urgent
Pain or bleeding with a possible pregnancy
Seek urgent assessment for a positive pregnancy test or possible pregnancy with one-sided or severe abdominal pain, shoulder-tip pain, fainting, severe dizziness, or significant bleeding. These can be signs of ectopic pregnancy or internal bleeding.
Severe pelvic pain with fever, vomiting, or feeling very unwell needs urgent care. During fertility treatment, rapidly increasing abdominal swelling, severe pain, breathlessness, reduced urination, faintness, or persistent vomiting also requires prompt contact with the treatment team or emergency service.
Questions people often ask
Does infertility always involve the person who would carry the pregnancy?
No. Egg, sperm, tubal, uterine, sexual, combined, or unexplained factors can contribute. Parallel evaluation prevents delay and blame.
Does a low AMH mean natural pregnancy is impossible?
No. It can inform ovarian response and context, but it does not measure egg quality or determine whether an individual can conceive naturally.
Does one abnormal semen analysis prove infertility?
No. Semen varies, and the result needs specialist interpretation with history and, when appropriate, repeat testing.
Should we wait a year if there is a known problem?
No. Absent periods, known tubal or testicular disease, prior cancer treatment, sexual dysfunction, recurrent loss, or older reproductive age supports earlier assessment.
Sources and evidence scope
This guide was researched using the WHO 2025 infertility guideline, NICE guideline NG257 (2026), the CDC infertility FAQ, the ASRM fertility-evaluation committee opinion, and the ACOG guide to evaluating infertility. Evidence and guidance were checked on August 20, 2026. Definitions, referral timing, treatment eligibility, law, funding, and emergency numbers vary by country.