Infertility is a medical condition characterized by the inability to achieve pregnancy after a considerable period of trying. The causes of infertility can be complex and involve one or both partners. Infertility affects millions of people, with roughly one in six individuals of reproductive age experiencing it during their lifetime. Factors that often diagnose infertility when a couple fails to conceive after 12 months of regular, unprotected intercourse. This challenge can arise from issues with the female partner, the male partner, or both. It’s important to remember that infertility is not uncommon and that medical help is available. In this article, we’ll explain key causes and risk factors, discuss how age and lifestyle can impact fertility, describe signs that might indicate a problem, and outline when to seek help from a specialist.
Infertility in Women: Common Causes
When it comes to infertility in women, there are several common causes and underlying conditions. Below are some of the major categories of female infertility causes:
- Ovulation problems: Disorders of ovulation are among the most frequent issues causing female infertility. If a woman isn’t ovulating normally, conception cannot occur. Often, ovulation problems are due to hormonal imbalances. These are hormonal infertility causes, such as polycystic ovary syndrome (PCOS) or thyroid dysfunction, that disrupt the monthly cycle. For example, PCOS is a syndrome of hormone imbalance that can prevent the ovary from releasing eggs, and thyroid disorders can also lead to irregular or absent ovulation. High levels of the hormone prolactin, extreme exercise, and eating disorders are other factors that can cause irregular ovulation. The good news is that many hormonal issues can be evaluated with blood tests and often treated with medication to restore regular ovulation.
- Fallopian tube damage or blockage: The fallopian tubes are the pathway for the egg to meet the sperm; if they are blocked or damaged, fertilization is difficult. Blocked fallopian tubes are commonly caused by scarring from pelvic infections or endometriosis. Pelvic inflammatory disease (PID), often a result of untreated sexually transmitted infections like chlamydia or gonorrhea, can lead to inflammation and scarring in the tubes, preventing eggs and sperm from meeting. Endometriosis, a condition in which tissue similar to the uterine lining grows outside the uterus, is another major cause. It can create scar tissue and adhesions that block tubes or impair their function. Even certain non-cancerous growths like uterine fibroids can occasionally block the tube openings or distort the uterus. If an egg can’t travel through a tube or a fertilized egg can’t reach the uterus, infertility will result.
- Uterine or cervical abnormalities: Structural problems in the uterus or cervix can also contribute to infertility in women. Uterine fibroids and polyps can interfere with the implantation of an embryo or even block the fallopian tubes in some cases. An abnormally shaped uterus might make it harder to carry a pregnancy. Cervical issues, such as an incompetent cervix or very thick cervical mucus that hinders sperm movement, are less common factors but can play a role. In most cases, these anatomic problems can be detected by imaging and sometimes corrected with surgery to improve fertility.
- Ovarian insufficiency (early menopause): Occasionally, a woman’s ovaries stop functioning normally well before the typical age of menopause. This condition, known as primary ovarian insufficiency, causes a woman to run out of viable eggs early. It can happen due to genetic factors, autoimmune disease, or even cancer treatments like chemotherapy. Women with this condition may have irregular or no periods and decreased fertility in their 20s or 30s. While rarer, it is an important cause of infertility to recognize, and women affected may consider options like donor eggs if they wish to conceive.
It’s clear that a variety of health issues can impact female fertility. Often, more than one factor may coexist. A thorough medical evaluation is needed to pinpoint specific causes. The encouraging news is that many of these problems are treatable through medications or surgery.
Infertility in Men: Common Causes
Male factors are an equally important piece of the puzzle. Infertility in men accounts for roughly one-third of infertility cases, and male issues can be the sole cause or a contributing cause even when female factors exist. Here are key causes and contributors to male infertility:
- Sperm production and function problems: Various medical conditions can affect how sperm are produced in the testicles or how they function. For instance, an undescended testicle can impair sperm production later in life. Genetic defects or chromosomal abnormalities may result in little to no sperm production. Hormonal disorders can also lead to poor sperm output. Certain infections are known to harm sperm-producing cells or ducts. For example, mumps infection in adolescence or adulthood can inflame the testicles (orchitis) and reduce fertility, and sexually transmitted infections can cause inflammation or scarring. Additionally, a condition called varicocele is a very common finding in infertile men. It’s believed to raise testicular temperature or cause oxidative stress, which negatively affects sperm quality. The good news is that varicoceles can often be surgically corrected, which may improve sperm counts.
- Blockages or ejaculation issues: Some men produce healthy sperm, but a blockage or functional issue prevents the sperm from being ejaculated normally. For example, prior surgeries or infections can block the vas deferens, preventing any sperm from appearing in the semen. Men with certain genetic conditions, like cystic fibrosis, often have an absence of the vas deferens tubes altogether. Ejaculatory problems can also cause infertility. This can include retrograde ejaculation. Male fertility test results, such as a semen analysis, might show no or very low sperm count in these cases despite normal hormone levels. Some sexual dysfunctions, like severe erectile dysfunction or premature ejaculation, can impede the delivery of sperm during intercourse, though these are usually treatable or bypassable issues.
It’s important to note that many male infertility causes are identifiable and some are treatable. It ensures that any male factors are addressed alongside female factors for the best chance of success.
Unexplained Infertility
Not every infertility struggle comes with a clear answer. In a significant number of couples, all standard tests and evaluations yield normal results. When doctors cannot identify a specific cause for infertility despite thorough evaluation, the condition is labeled unexplained infertility. This means everything seems to work on paper, yet pregnancy still isn’t occurring. Studies indicate that a considerable portion of infertile couples fall into this unexplained category.
Unexplained infertility can be frustrating for patients and doctors alike, because there’s no obvious target for treatment. However, just because the cause isn’t found does not mean pregnancy is impossible. Many couples with unexplained infertility do eventually conceive, sometimes with simple interventions or sometimes without any treatment at all. It’s possible that in cases of unexplained infertility, there may be subtle factors at play that our current tests can’t easily detect. These might include minor abnormalities in egg or sperm function, timing issues, or other biochemical factors not part of routine testing.
Doctors often manage unexplained infertility by focusing on optimizing natural fertility and then moving to assisted reproductive techniques if needed. They may advise timing intercourse correctly, making lifestyle improvements, or using ovulation tracking to maximize the chances each cycle. If those measures don’t help, treatments like fertility medications or intrauterine insemination (IUI) can be tried empirically. In many cases of unexplained infertility, assisted reproductive technologies (ART), such as in vitro fertilization, are ultimately very useful because they can bypass some potential unknown barriers and also allow closer observation of how the sperm and eggs interact in the lab. It’s encouraging to note that unexplained infertility is not hopeless. It may just require a bit of extra perseverance and possibly advanced treatments to achieve a pregnancy. Researchers continue to study these cases to better understand subtle factors that might be at work. As always, maintaining open communication with a fertility specialist is key so that you can decide on a plan if you fall into this category.
Infertility and Age
One of the biggest factors influencing fertility is age. The link between infertility and age is well-documented, especially for women. Women are born with all the eggs they will ever have, and both the quantity and quality of those eggs decline over time. In a woman’s early 20s, fertility is at its peak; by her 30s, it starts to drop and then declines significantly after age 35. Women in their mid-30s are only about half as fertile as they were in their early 20s. This decline accelerates as women approach their late 30s and early 40s, due to decreasing egg numbers and an increase in chromosomal abnormalities in the remaining eggs. By age 40, the chance of getting pregnant naturally in any given month is much lower than at 30, and by the mid-40s, natural conception becomes rare for most women. Eventually, menopause marks the end of natural fertility altogether.
Lifestyle Factors That Impact Fertility
Beyond medical conditions and age, there are numerous lifestyle factors that impact fertility in both women and men. Our everyday choices and overall health can significantly influence the chances of conception. The positive side is that many lifestyle factors are modifiable, meaning changes can improve fertility outcomes. Here are some key lifestyle and environmental factors to consider:
- Body weight and diet: Maintaining a healthy weight is essential for reproductive health. Women who are significantly overweight or underweight can experience ovulation problems. Excess body fat can lead to hormonal imbalances that interfere with regular ovulation. On the other hand, too little body fat can cause the menstrual cycle to stop. Men who are obese may have lower testosterone and sperm counts. Eating a balanced diet rich in nutrients supports overall fertility. Deficiencies in specific nutrients have been linked to fertility issues, so a well-rounded diet is recommended. If needed, losing even 5-10% of body weight or gaining weight to reach a healthier range can sometimes restore normal reproductive function, including regular ovulation.
- Smoking: Cigarette smoking is very harmful to fertility in both genders. In women, smoking accelerates the loss of eggs and can bring on earlier menopause; it’s also linked to higher miscarriage rates. In men, smoking can reduce sperm count and motility and damage sperm DNA. Significantly, smoking doesn’t just marginally affect fertility. Research suggests that tobacco use by either partner may be responsible for a significant percentage of infertility cases. In fact, smoking and tobacco use are estimated to play a role in roughly 13–15% of infertility cases. Quitting smoking can improve the chances of conceiving and is one of the best things you can do for your future baby’s health as well.
- Alcohol and substance use: Heavy alcohol consumption can impair fertility in both women and men. Women are often advised to avoid alcohol when trying to conceive because even moderate drinking might affect hormone levels and ovulation. Men who drink heavily can experience decreased sperm quality and count; alcohol can lower testosterone and lead to erectile difficulties as well. The safest approach for those actively trying to get pregnant is to limit or avoid alcohol. Similarly, use of illicit drugs or misuse of prescription drugs can harm fertility. Marijuana, for example, may disrupt ovulation in women and has been linked to lower sperm counts in men. Anabolic steroids are especially damaging to male fertility. Even opioid painkillers or other medications, if used long-term, could interfere with reproductive hormones. If you’re planning a pregnancy, it’s wise to review any substances or medications you use with a healthcare provider and minimize unnecessary exposures.
- Exercise and stress: Physical activity is generally good for fertility, especially in helping maintain a healthy weight and reducing stress. However, excessive exercise can sometimes negatively affect fertility, particularly in women. Athletes or individuals who exercise to the point of very low body fat may experience disrupted menstrual cycles. The key is moderation. Regular moderate exercise is beneficial, but extreme regimens might need to be scaled back if they are impacting hormone balance. Chronic stress, while not a direct cause of infertility, can contribute to hormonal changes and sexual dysfunction. Severe stress might lead some women to ovulate less consistently or some men to have reduced libido or sperm quality. Managing stress through methods like mindfulness or adequate rest can be helpful when navigating infertility, both for emotional well-being and potentially for improving outcomes.
- Environmental toxins: Our environment can expose us to various chemicals and toxins that may affect reproductive health. Prolonged exposure to pesticides, industrial chemicals, heavy metals, or radiation can harm eggs and sperm. Certain occupations have been associated with higher rates of infertility or miscarriage. It’s not always possible to avoid all environmental exposures, but taking precautions and reducing contact with known reproductive toxins might be prudent, especially when trying to conceive.
Adopting a healthy lifestyle can improve fertility prospects. Stopping smoking, limiting alcohol, maintaining a healthy weight through a balanced diet and exercise, and reducing stress are all steps that can boost your chances of pregnancy. These changes also create a healthier environment for a future pregnancy.
Signs of Infertility
One of the tricky aspects of infertility is that it often doesn’t have obvious outward symptoms. The signs of infertility can be subtle or even nonexistent until a couple tries to conceive. The primary sign, of course, is not getting pregnant despite regular unprotected intercourse. Generally, if a woman under 35 has tried for a year with no success, that in itself is considered a sign of a potential fertility problem. However, some additional clues and symptoms might hint at an underlying issue even before hitting those time benchmarks.
When to Get Help
Knowing when to seek professional help for fertility is crucial. As a general guideline, medical experts recommend seeing a fertility specialist (such as a reproductive endocrinologist) if you meet the following criteria: Under age 35 and not pregnant after 12 months of trying, or age 35 or older and not pregnant after 6 months of trying. In practical terms, if you’re a woman in your 20s or early 30s with no success conceiving after one year of regular, unprotected sex, that’s the time to schedule an evaluation. If you’re in your mid-30s, it’s prudent to seek help after six months of trying without success, because fertility declines faster at that age, and you’ll want to address any issues promptly. And for women at 40 or above, some doctors suggest consulting a specialist as soon as you decide to try for a baby, since time is a critical factor.
There are also special situations where you shouldn’t wait the full 6 or 12 months to get help. For example, if a woman has very irregular periods or no periods at all, it’s a sign of a possible ovulation problem. In that case, it’s worth seeing a doctor sooner because simply “waiting and trying” might not make sense if ovulation isn’t happening regularly. Similarly, if someone has a known condition that could impact fertility, they should talk to a fertility specialist early on, even before the typical trying period has elapsed. Women who have had repeated miscarriages might also benefit from an evaluation to look for causes of pregnancy loss.
Diagnosing Infertility (Tests and Evaluation)
Once you decide to seek medical help for possible infertility, the first step is a diagnostic evaluation. Both partners should be evaluated, since infertility can involve the woman, the man, or both. The diagnosis process typically includes a combination of medical history review, physical examinations, and specific fertility tests to pinpoint any issues. The doctor will ask detailed questions about your health history, sexual history, and lifestyle. Women will be asked about their menstrual cycle regularity, past pregnancies or miscarriages, pelvic pain, and any known health conditions. Men will be asked about prior injuries or surgeries, sexual function, and any history of infections or illnesses that could affect fertility. A physical exam will check for anatomical abnormalities. For women, the doctor may perform a pelvic exam to feel for ovarian enlargement or uterine irregularities; for men, the doctor will examine the testicles and scrotum for issues like varicoceles or abnormalities in size/structure.
Infertility Treatment Options
Facing infertility can be challenging, but the good news is that there are many infertility treatment options available today. Advances in medical science have created a wide spectrum of therapies, from low-tech solutions like medication or lifestyle changes to high-tech procedures like IVF. The appropriate treatment depends on the specific causes identified, the duration of infertility, and the couple’s personal preferences and situation.
It’s important to have a thoughtful discussion with your fertility doctor about which infertility treatment options make sense for you. Often, there is a stepped approach. A couple might start with medication and timed intercourse, then progress to IUI, and only move to IVF if those fail. In other situations, the doctor may advise going straight to IVF because other methods would likely be futile. Factors like cost, insurance coverage, and personal comfort with the technology also come into play. Throughout this process, mental health support can be very helpful, as infertility treatments can be stressful.
Fertility Clinics and IVF Specialists
If you’re dealing with infertility, you will likely find yourself working with a specialized clinic or doctor at some point. Fertility clinics are medical centers that focus on helping people achieve pregnancy, offering a range of advanced fertility clinic services under one roof. The physicians who lead these clinics are typically reproductive endocrinologists, essentially IVF specialists who have additional training beyond general obstetrics/gynecology to manage complex fertility issues and assisted reproductive technologies.
One of the advantages of seeking care at a fertility clinic is the comprehensive approach. For example, at a clinic like IVF Center Hawaii, patients have access to individualized care from an experienced IVF specialist and a full spectrum of services from evaluation through treatment. A fertility clinic can coordinate everything: they perform on-site ultrasounds and lab tests, have embryologists to handle IVF procedures, and often provide resources such as fertility counseling or acupuncture through their network. This integrated approach can be more convenient than piecing together services from different providers.
When choosing a fertility clinic or specialist, many people consider the clinic’s success rates. Fertility clinic success rates are usually reported as the percentage of cycles that result in live births, often broken down by treatment type and the woman’s age. In the United States, clinics are required to report their IVF success statistics to the Centers for Disease Control (CDC) and the Society for Assisted Reproductive Technology (SART), and these data are made public each year. While success rates can be a helpful benchmark, it’s important to interpret them carefully. Success rates vary based on the clinic’s patient population and the difficulty of cases they take on. A high success rate is encouraging, but a slightly lower rate doesn’t necessarily mean a clinic is “worse.” They might be treating older patients or more challenging cases. It’s often useful to look at success rates in your specific category. A good clinic will be transparent about its numbers and how they apply to you.
Beyond the numbers, factors like location, cost, and the clinic’s philosophy should also play into your decision. Infertility treatment can involve frequent appointments, so a conveniently located clinic can reduce stress. Financially, costs can vary, and not all clinics have the exact pricing or package options. Inquire about pricing for consultations, tests, and treatments, and check what your insurance may cover. Many clinics have financing programs or bundle plans for IVF cycles to help manage costs. You’ll want to feel comfortable with the doctor and staff. Compassion and trust are essential, as fertility journeys can be emotional. Don’t hesitate to schedule an initial consultation or even visit multiple clinics to find one that feels like the right fit for you.
Learning about infertility is an excellent way to advocate for yourself. With knowledge in hand and supportive professionals by your side, you can make informed decisions on your path to parenthood. Stay positive and proactive, and take it one step at a time. The road may be challenging, but the destination is worth every effort.
Sources
- World Health Organization (WHO) – Infertility Fact Sheet (28 November 2025) who.int
- NICHD (NIH) – Infertility and Fertility (Eunice Kennedy Shriver National Institute of Child Health & Human Development) nichd.nih.gov
- Cleveland Clinic – Infertility: Types, Causes, Symptoms, Diagnosis & Treatment my.clevelandclinic.org
- American Academy of Family Physicians – Lindsay TJ, et al. “Evaluation and Treatment of Infertility.” American Family Physician. 2015;91(5):308-314 aafp.org