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The Most Common Causes of Infertility

The Most Common Causes of Infertility

Around 1 in 7 heterosexual couples will experience fertility problems1. But what actually causes them? We asked top IVF specialist Mr Rehan Salim, Consultant at the esteemed Wolfson Fertility Centre at Hammersmith Hospital, to talk us through it.

Dr Rehan SalimHe told us: “A good fertility clinic will provide thorough screening for couples having trouble. If you’ve been trying to conceive for a year or more with no success, it’s a good idea to seek fertility testing. But if you are above the age of 35, you might not want to wait as long as that. Women (and actually men to a certain extent) have biological clocks, so really the sooner you uncover any roadblocks, the better.” At The Wolfson Fertility Centre, experts provide state of the art testing, and comb through a couple’s medical history in order to uncover any issues.

Here is a summary of the most common causes of infertility.

What Are The Most Common Causes Of Infertility In Women?

Ovulation Problems

Female infertility is most often the result of ovulation problems, Mr Salim told us. These include:

Polycystic ovary syndrome (PCOS)
Mr Salim said: “In women with PCOS, ovary follicles develop abnormally and accordingly don’t manage to ovulate an egg each month. It is estimated that around half of all women with PCOS are symptom-free, meaning you may not suspect you have it until you begin experiencing conception problems or miscarriages.”

Premature ovarian failure
This is when the ovaries stop functioning properly before a woman reaches 40.

Decline in ovarian reserve and egg quality due to age

Thyroid issues
Your thyroid gland produces hormones that regulate ovulation. Both an overactive thyroid gland and an underactive thyroid gland can prevent ovulation.

Cervical Mucus Issues
During ovulation, your cervical mucus thins out so that sperm can more easily make its way through it. If there are any mucus abnormalities this can make conception more difficult.

Fibroids (non-cancerous growths) either in or around your uterus may damage fertility. Sometimes they obstruct the fallopian tubes or make it impossible for a fertilised egg to implant in the womb.

Endometriosis syndrome causes little pieces of a woman’s womb lining to grow in other sites, for example the ovaries. This can cause damage to the ovaries or fallopian tubes, leading to infertility.

Pelvic Inflammatory Disease
“Pelvic Inflammatory Disease (PID) causes infection of the upper female genital tract (encompassing the ovaries, uterus and fallopian tubes). It can cause significant damage to the fallopian tubes and severely hamper an egg’s ability to reach the womb. PID is often the result of a sexually transmitted infection,” Mr Salim told us.

Here at Private Pregnancy UK we can help you find a Top Private Fertility/IVF Consultant or a Private Fertility/IVF Clinic or Hospital to guide you on your IVF journey.

What Are The Most Common Causes Of Infertility In Men?

“Fertility issues are all too often discussed as if they are just women’s worries, but this is not the case at all,” Mr Salim said. “In fact studies show the male factor in infertility accounts for around 40-50% of all cases2.

“The message to take home is, if you’re having trouble conceiving, never just assume the problem lies with the woman – both the male and female partner need to be checked out. That’s why at The Wolfson Fertility Centre we thoroughly assess both partners, leaving no stone unturned.”

Fertility problems in men are most commonly caused by the following issues…

Suboptimal Sperm

Typically, male infertility is caused by poor quality semen. Problems include:

  • Low sperm count or even the absence of sperm in the semen altogether
  • Low sperm motility, making it more difficult for the sperm to actually reach the egg
  • Abnormal sperm – the sperm may be shaped abnormally which makes it more difficult to swim and to fertilise the egg
  • Unexplained sperm abnormality

There is a connection between elevated scrotum temperature and a reduction in sperm quality but it’s still not known whether wearing loose underwear can help male fertility3.

Testicular Problems

The testicles are where sperm are produced and stored; accordingly, testicular problems can cause semen problems. Possible issues include:

  • Testicular cancer
  • Infection in the testicles
  • Surgery on the testicles
  • Testicular injury
  • A testicular problem since birth
  • One or more undescended testicles (when the testicle has failed to descend into the scrotum)

Ejaculation Problems

In around 5% of couples experiencing fertility issues, problems with sex are the main factor4. Obstacles include erectile dysfunction, failure to ejaculate and premature ejaculation.


Men with hypogonadism possess abnormally low testosterone levels, which can then affect sperm production. The problem can be caused by a number of factors including drug use, a tumour, or a chromosome abnormality.

Medicines and Drugs

Some medications can potentially create fertility issues. These include: chemotherapy drugs; sulfasalazine inflammatory medicine; some herbal remedies such as Tripterygium wilfordii root extract; and illegal drugs such as marijuana, cocaine, and steroid use for muscle building.

Unexplained Infertility

Mr Salim told us: “It is important to note that 25% of all screened couples will find their cases classified as unexplained infertility.1 However the good news is that such a classification does not necessarily mean that fertility interventions such as IVF will not work.”

He added: “The right fertility treatment for a couple will depend on a complex range of factors. That’s why the finest testing and thorough medical history reviews are so vital. At The Wolfson Fertility Centre we comb through a couple’s specific fertility profile in order to best tailor an IVF plan (if necessary), especially for them.

“Yes, it takes a lot of time and effort. But I always say that this effort is nothing compared to the joy of finally becoming a parent.”

If you’re worried about fertility, call The Wolfson Fertility Centre to find out more about their gold standard tests and treatments on 020 3313 4411. Alternatively you can go to one of their monthly fertility open evenings to speak to their experts in person.




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