Infertility in Women & Men: 5 Causes and Treatments

Infertility is defined as the inability to conceive after 12 months of regular unprotected intercourse — or 6 months if you’re over 35. It affects roughly 1 in 8 couples of reproductive age, making it one of the most common medical conditions people face during their reproductive years. The emotional weight is significant, but so are the treatment options available today.

What Causes Infertility in Women?

Female infertility accounts for about one-third of all infertility cases. The most common causes include:

• Ovulatory disorders: Conditions like PCOS (polycystic ovary syndrome) disrupt regular ovulation and are the most common single cause of female infertility. Hypothyroidism and hyperprolactinemia also fall into this category.
• Diminished ovarian reserve: The quantity and quality of eggs declines with age — significantly after 35. Low AMH levels and a low antral follicle count are key indicators.
• Fallopian tube blockage: Usually caused by prior pelvic infections, endometriosis, or previous ectopic pregnancies. Blocked tubes prevent sperm from reaching the egg.
• Endometriosis: Tissue similar to the uterine lining grows outside the uterus, causing inflammation, scarring, and often significant pain. It affects roughly 10% of women of reproductive age.
• Uterine abnormalities: Fibroids, polyps, or structural issues with the uterine cavity can prevent implantation. Most are identifiable through a standard uterine evaluation.
• Age: Egg quality and quantity both decline naturally with age. This is the single most predictable factor in female fertility — which is why early evaluation matters if you’re over 35.

For women who aren’t ovulating regularly, medications can often restore ovulation. When the issue is structural or age-related, IVF is typically the most effective path forward. You can read more about how age specifically affects outcomes in our guide on IVF for women over 40.

What Causes Infertility in Men?

Male factor infertility is involved in roughly 40–50% of all infertility cases — either as the primary cause or as a contributing factor. It’s consistently underdiagnosed because women are more often evaluated first. Common causes include:

• Low sperm count (oligospermia): Fewer sperm means lower odds of reaching and fertilizing an egg in any given cycle.
• Poor sperm motility (asthenospermia): Sperm that can’t swim effectively can’t reach the egg even if the count is normal.
• Abnormal sperm morphology: Unusually shaped sperm have lower fertilization rates.
• Varicocele: Enlarged veins in the scrotum increase testicular temperature, which damages sperm production. It’s the most common correctable cause of male infertility.
• Hormonal imbalances: Low testosterone or disrupted FSH/LH signaling reduces sperm production.
• Lifestyle factors: Smoking, heavy alcohol use, anabolic steroids, heat exposure (hot tubs, tight clothing), and obesity all negatively affect sperm quality.

Many couples don’t realize that male factor issues are just as common as female ones. A basic semen analysis is quick, inexpensive, and should be done early in any infertility workup — not as an afterthought. Our male infertility guide covers the most common misconceptions about what does and doesn’t affect sperm.

What Is Unexplained Infertility?

In roughly 10–15% of cases, standard testing doesn’t find a clear cause. This is called unexplained infertility — a frustrating diagnosis that doesn’t mean nothing is wrong, just that current testing hasn’t identified it. Many of these cases involve subtle egg quality issues, fertilization problems, or implantation factors that aren’t captured by routine tests.

Treatment for unexplained infertility typically starts with ovulation induction and IUI, then moves to IVF if those aren’t successful. IVF also serves a diagnostic function — watching how eggs fertilize and develop in the lab often reveals issues that couldn’t be seen beforehand.

What Are the Treatment Options for Infertility?

Treatment depends entirely on the cause. The most common approaches include:

• Ovulation induction: Oral medications or injectable IVF medications stimulate ovulation in women who aren’t ovulating regularly.
• IUI (intrauterine insemination): Prepared sperm is placed directly into the uterus around ovulation. Less invasive than IVF and often tried first for mild male factor or unexplained infertility. See our IVF vs IUI comparison for when each is appropriate.
• IVF (in vitro fertilization): Eggs are retrieved, fertilized in a lab, and the resulting embryo is transferred to the uterus. The most effective ART option for most diagnoses.
• Egg donation: For women with severely diminished ovarian reserve or poor egg quality, donor eggs combined with IVF offer significantly higher success rates.
• Surgery: Fibroids, polyps, blocked tubes, varicocele, and endometriosis can often be treated surgically before proceeding with IVF.
• Lifestyle changes: Weight management, stopping smoking, reducing alcohol, and improving diet and sleep all affect fertility outcomes. Our fertility diet guide covers the most evidence-backed dietary changes.

According to RESOLVE: The National Infertility Association, about 85–90% of infertility cases are treated with conventional medical therapies — not IVF. That said, IVF remains the most effective single treatment when other approaches haven’t worked, and medication costs can be a significant barrier for many patients.

Fast IVF helps reduce that barrier by supplying European-brand IVF medications at prices well below US retail. Browse the full product catalog or request a free price quote once your doctor has prescribed your protocol.

Frequently Asked Questions About Infertility

When should I see a doctor about infertility?

If you’re under 35 and have been trying for 12 months without conceiving, it’s time to get evaluated. If you’re 35 or older, that window shortens to 6 months. If you have a known condition like PCOS, endometriosis, irregular cycles, or a history of pelvic infections, don’t wait — get evaluated sooner. Earlier diagnosis means more treatment options.

Is infertility always a woman’s problem?

No — and this is one of the most persistent and damaging myths around infertility. Male factor is involved in roughly half of all cases. Both partners should be evaluated at the same time. Waiting to test the male partner only after multiple failed female treatments wastes time and money. A semen analysis is the most important first step for the male partner.

Can infertility be prevented?

Some causes can’t be prevented — age-related decline, genetic factors, and certain medical conditions fall into this category. But many lifestyle-related factors can be addressed: maintaining a healthy weight, not smoking, limiting alcohol, managing chronic conditions like diabetes or thyroid disease, and getting regular health screenings. Early fertility preservation through egg freezing is also an option for women who want to protect their options. See our egg freezing guide for more on when this makes sense.

How does IVF work for infertility treatment?

IVF involves stimulating the ovaries with injectable medications to produce multiple eggs, retrieving those eggs, fertilizing them in a lab, and transferring the resulting embryo to the uterus. It bypasses many of the natural barriers to conception — blocked tubes, sperm delivery issues, ovulation problems — which is why it’s effective across such a wide range of diagnoses. Our infertility overview covers the full diagnostic and treatment pathway in more detail.

How much do IVF medications cost and how can I reduce that cost?

At US retail pharmacies, a full IVF medication protocol typically runs $3,000–$6,000 per cycle. Fast IVF sources the same European-brand medications — identical active ingredients, same manufacturers — at a fraction of those prices. Check our IVF medication costs guide for a detailed breakdown of what patients typically save per cycle.