A guide to understanding the diagnosis of unexplained infertility

If you’ve done the run-around with fertility specialists, vitamins, ovulation tracking and more to try and get pregnant, an ‘unexplained infertility’ diagnosis can feel like a punch to the guts. You’re healthy and doing all the right things to get pregnant, but it’s just not happening. And there’s no good reason why. 

Before you berate your seemingly useless doctor for not having any answers for you, or give up on the whole ‘having kids’ thing, know that you’re not alone in experiencing unexplained fertility issues. And you’re certainly not out of options either.

What is unexplained infertility?

This is the term given to couples when they’ve been unsuccessfully trying to conceive for over a year, and all potential causes have been ruled out. That is to say:

  • Your uterus is in good knick.
  • You’re ovulating regularly.
  • Your fallopian tubes are healthy and unblocked.
  • You’ve got a good reserve of healthy eggs.
  • Your partner or donor’s sperm is lookin’ mighty fine. (Well, as far as sperm goes.)

Yet despite all this, you’re just not falling pregnant. It’s frustrating as hell.

It may provide some sense of comfort to know that about one in six Australian couples experience fertility issues. And in about 20 per cent of those cases, it’s for no apparent reason (AKA unexplained infertility).

If you get diagnosed with unexplained infertility, you’ll probably be bursting with questions about what’s causing it and WTF you can do about it. Thing is, there isn’t a known cause (hence, ‘unexplained’). 

But there could be some contributing factors.

What might be some unexplained infertility causes?

Undiagnosed underlying conditions

If you’ve been looking into unexplained infertility causes, your doctor should have ruled out things like PCOS, endometriosis, and issues with your guy’s sperm (or donor sperm). But as much as we hate to admit it, medical science hasn’t uncovered everything there is to know. There could be links between certain health conditions and fertility that doctors don’t yet know about. 

For example, there’s ongoing research into how unexplained fertility issues could be related to some autoimmune conditions like thyroid dysfunction, diabetes, or coeliac disease. 

There’s also discussion about whether a mild form of endometriosis could be linked to unexplained infertility, even though it may not contribute noticeable barriers to falling pregnant (like ovulation issues or fallopian tube blockages).

The vaginal environment and sperm

Eggs + Sperm + Healthy Uterus = Guaranteed Baby, right?

In theory, yes. But when you think about the actual process of sperm fertilising an egg, it’s a wonder that any women fall pregnant ever! Talk about the ultimate game of right-place- right-time. 

I mean, let’s break this down. 

The sperm (which has to be good quality sperm) needs to be ejaculated (requiring someone to orgasm – sometimes a feat in itself), then needs to travel up the cervix into the uterus (bypassing potentially hostile cervical mucus and any blockages or weirdness), then needs to find a good-quality egg to fertilise. And even then, the conditions of your uterus and body need to be perfect for the fertilised egg to develop into a baby.


So unexplained infertility could happen if the eggs or sperm aren’t great quality (which you can only know if they’re examined under a microscope), if your endometrium (uterus lining) doesn’t do what it’s meant to do, or if the fertilised egg just decides not to develop for no good reason.

Unknown factors

As already mentioned, we don’t know everything about the human body yet. Maybe going for a walk on a 24-degree day when the moon is out and Mercury is in retrograde spells unexplained fertility. We don’t know. 

What we do know is that some lifestyle and environmental factors seem to affect fertility in both men and women. Being over or underweight, smoking or using drugs, over-exercising, or even being exposed to certain chemicals and preservatives can increase the time it takes to fall pregnant. An ongoing study called ​​Longitudinal Investigation of Fertility and the Environment (LIFE) Study is looking into all this stuff. Stay tuned for more insights!

Nothing at all

The average healthy and fertile couple has about a 30 per cent chance of falling pregnant each month as it is. So perhaps there’s not actually anything wrong with you, you just haven’t fallen pregnant naturally yet. Just like I haven’t won the lottery yet (but your chances are probably higher than that happening, seeing as I don’t buy lotto tickets).

Your unexplained infertility treatment options 

So you’ve been slapped with an unexplained infertility diagnosis. What now? You’ve got a few options.

Wait it out

This is called ‘expectant management’ of unexplained infertility, and it means that you just keep trying. You could make some lifestyle adjustments and buckle down in your efforts to fall pregnant to achieve this. For example:

  • Eat a healthy diet, quit smoking or drinking to excess, get some regular physical activity in, and prioritise sleep and health management so your body is in prime condition to grow a baby.

  • Get a general preconception health check done. Run any medications you’re taking past your doctor and ensure that your overall health is tip top. Get their advice on diet changes to achieve an in-range BMI, and a recommendation on prenatal supplements to boost your nutrient intake.

Explore different ways to get pregnant

If sex isn’t doing the very thing it’s meant to do, there’s always the option of trying to conceive without a penis being directly involved (shout-out to you mamas doing this anyway when exploring lesbian pregnancy options!). 

So there are two key ways you can try to bypass unexplained fertility issues at the point of conception:

Unexplained infertility and IUI (intrauterine insemination) – Involves inserting washed and primed sperm into your uterus with a catheter, for the best chances of fertilisation. Your fertility specialist might recommend boosting your chance of conception by taking medication beforehand.

Unexplained infertility and IVF (in vitro fertilisation) – Involves having a fertilised egg inserted directly into your uterus, along with taking medication to ensure your body is producing the right hormones for pregnancy. Many women turn to IVF for unexplained fertility treatment when IUI hasn’t done the trick.

Flush your tubes out

Even if your fallopian tubes don’t appear to have any blockages, tubal flushing has been shown to increase pregnancy rates. It’s done in a fertility clinic, and involves a doctor inserting a tube into your cervix, then flushing a water or oil-based solution into your uterus. Yikes. But hey – research shows “a statistically significantly higher pregnancy rate in couples with unexplained infertility randomised to a single tubal flush”. Maybe a flush is all it takes.

A final word on unexplained infertility

It’s not over yet.

If you’re over 35 and getting worried about your chances of ever having a family, we get your panic. It’s especially hard to deal with unexplained infertility when all your friends are popping babies out and it’s just not happening for you. 

But girl, your journey to motherhood doesn’t have to be finished with this diagnosis. Getting pregnant can be hard work. Heaps of couples with unexplained fertility issues go on to birth beautiful, healthy babies. 

If you’re not doing well emotionally, please get some psychological support because this stuff is TOUGH. You don’t have to go through this alone.

Read next: 5 ways to get pregnant without sex

Verywell Family, Understanding the Diagnosis of Unexplained Infertility

Victorian Assisted Reproductive Treatment Authority, Suspecting infertility

Quaas, Alexander, and Anuja Dokras. Diagnosis and treatment of unexplained infertility. Reviews in obstetrics & gynecology vol. 1,2 (2008): 69-76.

Schattman GL, Esteves SC, Agarwal A. Unexplained Infertility: Pathophysiology, Evaluation and Treatment. New York: Springer New York; 2015.

Advanced Fertility Center of Chicago, Unexplained Infertility Background, Tests and Treatment Options

Newlife IVF, Unexplained infertility – how do we fix it if we don’t know what’s wrong?

The Eunice Kennedy Shriver National Institute of Child Health and Human Development, What lifestyle and environmental factors may be involved with infertility in females and males?

Verywell family, Getting Pregnant With Unexplained Infertility

Nugent D, Watson AJ, Killick SR, Balen AH, Rutherford AJ. A randomized controlled trial of tubal flushing with lipiodol for unexplained infertility. Fertil Steril. 2002 Jan;77(1):173-5. doi: 10.1016/s0015-0282(01)02925-9. PMID: 1177961

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