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UNEXPLAINED INFERTILITY

Unexplained infertility is more common than you think. If tests show no clear cause, we can help you move forward with expert care and proven treatments.

Understanding unexplained infertility

Infertility is often thought of as a “women’s issue,” but male and female factors contribute equally to conception. One in six couples experience difficulties conceiving, and approximately 50% of fertility challenges involve male factors. 

For some couples struggling to conceive, standard fertility tests—such as semen analysis for men and ovarian reserve testing for women—show no obvious problems yet pregnancy still doesn’t happen. When there is no clear explanation for this, it is known as unexplained infertility. 

Unexplained infertility is a diagnosis of elimination, meaning all known causes must be ruled out first. Your doctor will conduct a full fertility assessment before reaching this diagnosis. You may be given the diagnosis of unexplained infertility if: 

  • The male partner’s semen analysis is normal (sperm count, movement, and shape within standard ranges). 
  • The female partner has regular ovulation, open fallopian tubes, and a normal ovarian reserve. 
  • No other medical or genetic factors are identified. 

This diagnosis can feel frustrating and uncertain. But unexplained does not mean untreatable. With expert guidance, and tailored fertility treatments, we can help you move forward. 

How is fertility usually assessed?

Fertility testing involves assessing both male and female factors.

Male fertility testing: 

Sperm count
The number of sperm in a sample, which determines overall sperm availability. 

Sperm motility
The ability of sperm to move effectively towards the egg, crucial for natural conception. 

Sperm morphology
The shape and structure of sperm, as abnormalities can affect fertilisation. 

Female fertility testing: 

Evidence of ovulation
This can be confirmed by a regular menstrual cycle, positive ovulation test kids, blood tests or ultrasound scans. 

Ovarian reserve testing
Blood tests measuring AMH (Anti-Müllerian Hormone) help assess egg quantity. 

Tubal patency tests
A HyCoSy or HSG test checks if the fallopian tubes are open and functioning, however, this isn’t always necessary. 

Endometrial health
The uterine lining is assessed for implantation suitability. 

What are the possible causes of unexplained infertility?

Even if initial test results appear normal, several underlying factors could be affecting fertility. Identifying these causes can help tailor treatments for better outcomes. 

Sperm DNA fragmentation

Sperm carries genetic material needed for conception and embryo development. If this DNA is damaged—known as sperm DNA fragmentation—it can lead to: 

  • Reduced fertilisation rates 
  • Poor embryo quality and failed implantation 
  • Higher miscarriage risk due to genetic instability 

DNA fragmentation cannot be detected in a standard semen analysis, but advanced sperm testing can identify the issue. A high level of DNA fragmentation may require lifestyle changes, antioxidant therapy, or specific fertility treatments such as Intracytoplasmic Sperm Injection (ICSI). 
Egg quality and age-related factors While ovarian reserve tests measure egg quantity, egg quality is harder to assess. As women age, egg quality naturally declines, increasing the risk of chromosomal abnormalities that can affect fertilisation and implantation. 
Oxidative stress and reproductive health

Oxidative stress occurs when there’s an imbalance of free radicals and antioxidants in the body, leading to damage in both sperm and egg cells. Common causes include: 

  • Poor diet lacking essential vitamins and minerals 
  • Smoking, excessive alcohol consumption, and recreational drug use 
  • Exposure to environmental toxins such as pesticides, heavy metals, and air pollution 
  • High stress levels, which can increase cortisol and disrupt hormone production 
  • Heat exposure (e.g., frequent sauna use, tight underwear, or prolonged laptop use on the lap) 

Reducing oxidative stress through dietary changes, quitting smoking, reducing alcohol intake, and taking antioxidant supplements can improve fertility health for both men and women. 
Undiagnosed hormonal imbalances

For men, testosterone, FSH, LH, and prolactin levels impact sperm production. For women, oestrogen, progesterone, FSH, and LH regulate ovulation and reproductive function. Even slight imbalances can affect fertility. 

A hormonal assessment can identify imbalances and help guide treatments such as hormone therapy or medication adjustments. 
Immune system factors

In some cases, the immune system may mistakenly attack sperm, a condition known as anti-sperm antibodies. Similarly, some women may have an overactive immune response in the uterus, which could interfere with implantation. 

Testing for immune-related fertility issues can help determine if these factors are affecting conception. 
Lifestyle and environmental factors

Modern lifestyles can significantly impact fertility. Key factors include: 

  • Chronic stress – Disrupts hormone balance and reproductive function. 
  • Diet and nutrition – Deficiencies in key nutrients like folate, zinc, vitamin D, and omega-3 fatty acids can impact fertility. 
  • Alcohol and smoking – Linked to reduced sperm quality, ovulation irregularities, and DNA integrity issues. 
  • Obesity – Higher BMI is associated with hormonal imbalances and poorer reproductive health. 
  • Medications and medical history – Some medications, past infections, or surgeries (such as testicular surgery or endometriosis surgery) can affect fertility. 

How common is unexplained infertility?

Unexplained infertility affects many couples. While male and female infertility factors account for most fertility challenges, research suggests that up to 30% of cases have no immediately obvious cause. 

Although unexplained infertility lacks a definitive diagnosis, advancements in fertility testing and treatments offer hope. Many couples successfully conceive with targeted interventions and lifestyle modifications. 

What are the next steps?

If you’ve been diagnosed with unexplained infertility, there are several options to help you move forward: 

Lifestyle optimisation

Certain lifestyle changes can boost sperm health and improve fertility outcomes, including: 

  • A diet rich in antioxidants, healthy fats, and essential vitamins. 
  • Reducing alcohol and quitting smoking. 
  • Managing stress through relaxation techniques. 

  • Avoiding excess heat exposure (such as hot tubs and tight clothing) 
Advanced fertility testing

Beyond standard semen analysis, advanced tests can provide deeper insights, including: 

  • Sperm DNA fragmentation test – Assesses sperm DNA integrity. 
  • Oxidative stress test – Measures free radical damage in sperm. 
  • Comprehensive hormone panels – Identifies subtle hormonal imbalances. 
  • Immune function testing – Assesses potential immune-related fertility issues. 
Fertility treatment

If lifestyle changes and advanced testing still don’t provide a clear answer, assisted fertility treatments may offer the best route forward: 

  • Sperm freezing – If sperm quality fluctuates, freezing a sample for future use can be beneficial. 

Each treatment is tailored to your specific needs, ensuring the best possible chance of success.