Inflammation and Infertility: The Missing Piece in Unexplained Infertility?

If you’ve ever been diagnosed with unexplained infertility, you know how frustrating that lack of clarity can be. Not having a concrete explanation for why your body isn’t doing the one thing you want it to do can feel so defeating. And in some ways, when there’s no medical cause that experts can point to, it puts even more pressure on the patient to “fix” the problem.

Speaking of vague, tough-to-understand medical issues: Inflammation has become something of a buzzword, both on social media and in real life. But despite how often it’s discussed, it can be tough to know what exactly inflammation is and how it affects your body.

And now, thanks to a blog post published by Harvard Medical School, we’re left wondering: Could inflammation be a factor that affects fertility?

But first: What is inflammation? (And why should you care when TTC)

Inflammation isn’t automatically a bad thing. It’s part of how your body protects and repairs itself.

Inflammation occurs when your body encounters an agent (think a bacteria, virus, or injury), and your body reacts by sending out inflammatory cells and cytokines, proteins that help your body produce more inflammatory cells for protective measures.

Inflammation can be acute (think: a response to illness or injury) or chronic (which occurs when your body continues to send these signals even if there's no obvious danger causing this reaction). Signs of acute inflammation can be easy to spot (like redness or swelling after an injury), while chronic inflammation can affect the body in less obvious ways (think joint pain, fever, or fatigue).

When you’re trying to conceive, that chronic kind is the one worth paying attention to. Unlike acute inflammation, chronic inflammation can quietly interfere with reproductive processes over time.

A 2025 review published in Reproduction for the Society for Reproduction and Fertility found that chronic inflammation is linked to disrupted ovulation, reduced egg quality, and changes in the uterine environment that can make implantation harder. Many fertility-related conditions, including endometriosis and PCOS, are also associated with higher levels of inflammatory markers.

Inflammation can also affect hormones. According to a 2013 study in Steroids, inflammatory cytokines can interfere with insulin signaling and ovarian hormone production, both of which play a key role in regular cycles and ovulation.

None of this means your body is working against you; it just means your immune system may be stuck in a prolonged “on” state. Understanding chronic inflammation’s impact on the body may help explain why fertility is about more than timing alone and why addressing underlying inflammation can be an important part of the TTC picture.

What's the connection between inflammation and fertility?

Inflammation and fertility are linked through what’s often called the inflammatory cascade. This is the chain reaction your immune system triggers when it releases cytokines and other signaling molecules. In small, well-timed amounts, these signals actually support reproduction. Ovulation, implantation, and early placental development all rely on controlled inflammatory responses.

The problem starts when inflammation becomes excessive or chronic. Ongoing immune activation can disrupt that balance. Elevated inflammatory cytokines have been shown to interfere with ovarian hormone production, follicle development, and even endometrial receptivity.

There’s also evidence that inflammation affects blood flow and cellular communication in reproductive tissues. A 2024 review for Reproductive Medicine and Biology found that persistent inflammation can negatively influence embryo implantation and early pregnancy maintenance by changing how the immune system interacts with the uterus.

While there’s no clear answer at the moment, the Harvard blog, written by Robert H. Shmerling, MD, breaks down research that aims to identify the relationship between inflammation and fertility. He raises an important question: Could inflammation be behind cases of unexplained infertility?

Based on his review of the research, inflammation’s ability to affect fertility is a real possibility. That doesn’t mean inflammation is the whole story, but it does help explain why some fertility challenges feel frustratingly hard to pin down.

Can inflammation cause infertility?

There’s no clear "yes" or "no" yet, but what scientists do know is that inflammation plays a role in many processes tied to reproduction.

One of the biggest impacts is on ovulation. Chronic inflammation can disrupt the hormonal signals that help follicles mature and release an egg. Elevated inflammatory cytokines can interfere with ovarian function and ovulatory regularity, making cycles less predictable or even anovulatory.

Those same cytokines may also affect egg quality. Inflammatory signaling has been linked to oxidative stress in ovarian tissue, which can damage developing eggs and reduce their developmental potential, as outlined in a 2025 study in MDPI Cells.

Inflammation also matters post-ovulation. A receptive uterine lining requires a carefully timed immune response. Chronic or excessive inflammation can alter endometrial blood flow and cellular communication, making implantation more difficult. A 2023 review for the National Library of Medicine found that chronic inflammatory states are associated with reduced endometrial receptivity and early implantation failure.

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And inflammation is not just a female fertility issue. In men, systemic inflammation has been associated with reduced sperm concentration, motility, and increased DNA fragmentation. A 2024 study in Northern Clinics of Istanbul linked inflammatory markers to poorer semen parameters.

All of this highlights a simple truth: fertility relies on a well-functioning immune system. When inflammation becomes excessive or chronic, conception can become harder for everyone involved.

Anti-inflammatory diet for fertility

An anti-inflammatory diet is a way of eating that can help calm chronic inflammation and support overall metabolic and hormonal health, which matters when you’re trying to conceive.

At its core, this nutrition style emphasizes whole, minimally processed foods. Think fruits, vegetables, whole grains, legumes, nuts, seeds, olive oil, and fatty fish. These foods are rich in antioxidants, fiber, and healthy fats that help regulate inflammatory pathways. On the flip side, diets high in ultra-processed foods, refined carbohydrates, added sugars, and trans fats have been linked to higher inflammatory markers.

Research on fertility outcomes is still evolving, but there are some promising signals. Several studies found that women who adopted low-inflammatory diets (such as the Mediterranean diet) had higher rates of successful pregnancies after IVF, while similar dietary patterns are associated with better sperm parameters in men, according to a 2024 review in Frontiers in Nutrition.

That said, diet isn’t a magic switch. “While recent research is intriguing, there’s not enough evidence to show that an anti-inflammation action plan will improve fertility. A plant-based diet, such as the Mediterranean diet, and other measures considered part of an anti-inflammatory lifestyle, improve heart health and have many other benefits,” Dr. Smherling writes. “It’s not clear if this is directly due to reducing inflammation. But this approach comes with little to no risk. And abundant convincing evidence suggests it can improve health and even fight disease.”

For real life, keep it simple. Build meals around plants, add protein and healthy fats, batch cook when you can, and aim for progress, not perfection. Small, consistent choices add up.

How to reduce inflammation for fertility

When it comes to lowering excessive inflammation, stress management matters more than it gets credit for. Chronic psychological stress has been shown to increase inflammatory markers like C-reactive protein and proinflammatory cytokines. A 2021 article for BJPsych Advances explains that ongoing stress can keep the immune system in a heightened inflammatory state, which may interfere with reproductive hormone signaling.

Practices like regular movement, mindfulness, therapy, breathwork, or even better sleep routines may help bring that stress response down over time. Remember: there's no single “right” way to do this, just what works for your life.

While it’s still somewhat unclear (even experts haven’t come to a specific consensus on how to lead an anti-inflammatory lifestyle), per Dr. Shmerling’s recommendations, a few simple changes can set you on the right path. Eat more plant-based foods, healthy fats, and whole grains; stop smoking or vaping; get enough sleep; avoid excess alcohol; and exercise regularly. You know, all the stuff you’re likely already doing to increase your odds of getting pregnant… comforting pint of ice cream included.

Next steps: Addressing inflammation when TTC

If inflammation feels like a possible piece of your fertility puzzle, the next step doesn’t have to be overwhelming. Start with information. You can talk with your doctor about whether testing makes sense for you, including markers like C reactive protein, erythrocyte sedimentation rate, insulin resistance, or condition-specific indicators if you have symptoms that point that way.

If you have a pre-existing medical condition that could be contributing to excessive inflammation, be sure to chat with your provider about making sure it is well-managed.

From there, think personalized, not prescriptive. An anti-inflammatory plan works best when it fits your body, your budget, and your real life. That might mean adjusting how you eat, managing stress differently, or addressing an underlying condition with medical support.

It’s also okay to ask for more help. If you’re dealing with unexplained infertility, recurrent loss, chronic conditions, or long-term TTC stress, additional support from a reproductive endocrinologist, dietitian, or mental health professional can make a real difference.

Set realistic expectations. Inflammation doesn’t resolve overnight, and fertility changes often take months, not weeks. That timeline can feel frustrating, but it’s normal.

Most importantly, remember this: small, sustainable changes beat perfect plans you can’t maintain. You’re not trying to fix your body. You’re learning how to support it, one doable step at a time.