Coeliac disease is a condition where your immune system attacks the small intestine when you eat gluten, which makes it harder for you to absorb nutrients. Gluten is found in foods containing wheat, rye or barley – essentially, delicious things like bread, pasta, cake and beer. According to the NHS, usual symptoms include stomach pain, diarrhoea, constipation, bloating and indigestion. So, you think it’d be obvious if you had coeliac, right? Unfortunately, it’s not as simple as that.

Coeliac UK reports that one in 100 people in the UK have coeliac disease. It’s estimated that only 36% of cases in the UK have been diagnosed, with a whopping half a million people thought to be unknowingly living with the disorder. The reason for this is that mild symptoms overlap with more commonly diagnosed gut disorders like IBS, while some people have what’s known as silent (or asymptomatic) coeliac disease. This is where patients don’t present with the typical digestive symptoms, instead complaining of things like extreme fatigue or skin problems.

The disorder is hereditary and can develop at any age, with reported cases higher in women than men. While there’s no cure, symptoms can be controlled by avoiding gluten. So, what’s all this got to do with fertility?

A 2018 Danish study of 69,485 women showed that prior to being diagnosed, women with coeliac disease had 11 more miscarriages and 1.62 more stillbirths per 1,000 pregnancies than those without the disease. In the two years before diagnosis, they also had 25 fewer pregnancies per 1,000. Later research revealed that women with unexplained infertility are three times more likely to have undiagnosed coeliac disease than those with healthy fertility.

“Nobody really understands why subfertility is related to undiagnosed coeliac disease,” explains Professor David Sanders, NHS consultant, professor of gastroenterology at The University of Sheffield, and chair of Coeliac UK’s health advisory council.

“I think of it in very simplistic terms – if I’m trying to conceive and I’ve got a number of vitamin deficiencies, I’m not in tip-top condition. And now I’m wanting my body to carry new life – it’s not going to do that. There’s been a lot of work done over the years trying to look at mechanisms and looking at different hormones and so on, but no one’s really come up with an answer.”

Dr Deepali Misra-Sharp is an NHS GP and clinical lead for women’s health at Lordswood Medical Group. She tells us how malabsorption of vitamins essential to reproductive health (like folic acid, iron, zinc and selenium) may lead to hormonal imbalances and conditions like irregular or absent menstruation.

“Coeliac disease’s autoimmune response can potentially interfere with reproductive processes, contributing to issues like recurrent miscarriages or trouble with implantation,” she adds. “The underlying inflammation and immune reactivity are thought to play a role, though more research is needed to fully understand the mechanisms.”

Professor Sanders explains that the medical community is still playing catch-up because knowledge of the disease has changed greatly over the years. “You can almost understand why it’s not being picked up because everyone was taught that symptoms need to be really severe,” he says. “Then there are people with non-specific symptoms like fatigue who are presenting to doctors who aren’t specialist gut doctors and who won’t necessarily test you.”

After talking to a number of women who experienced years of subfertility before being diagnosed with coeliac, it seems apparent that it’s not on the radar for some doctors when it comes to infertility.

Rebecca* experienced three recurrent miscarriages before falling pregnant with her son after 10 months of cutting out gluten: “After my third miscarriage, I was given blood tests by the NHS and a scan for uterine abnormality which all came back normal. Coeliac was never addressed – my own research and suspicion led me to it.”

Thankfully, some doctors are more on the ball. “I had my son in 2021 and since then have had two second trimester miscarriages,” shares Jessica. “I went to my GP with tiredness, wanting them to test my iron. They looked at my miscarriage history and decided to test for coeliac – here I am, three weeks post-diagnosis.”

“As a GP, coeliac disease should come into consideration for patients with unexplained infertility if other common causes such as hormonal imbalances, anatomical issues and lifestyle factors have been ruled out,” advises Dr Misra-Sharp. “According to NICE guidelines, testing for coeliac disease is recommended for patients with unexplained subfertility or recurrent miscarriages.”

While the stats sound scary, it’s important to note that once diagnosed and on a gluten-free diet, the pregnancy complication risk rate is the same as that of women who don’t have coeliac.

“On a gluten-free diet, the intestinal lining can heal, nutrient absorption improves and the autoimmune response calms, which generally helps restore reproductive health,” explains Dr Misra-Sharp. “Clinically, many patients see an improvement in their fertility within six to 12 months of following a gluten-free diet, although the exact timeframe varies based on factors like the length of time coeliac disease went undiagnosed and individual health profiles.”

Michaella Mazzoni, a hormone nutritionist who has personal experience with IVF and infertility, recommends powder, spray or liquid nutrient supplements to coeliac clients while their gut lining is healing: “These tend to be easier to absorb than capsules.”

A word of warning before you cut out gluten entirely…

If you’re experiencing fertility issues, you might be tempted to cut out gluten after reading this. However, Professor Sanders warns not to do this without consulting a medical professional, as you need to be consuming gluten to get tested (and if you don’t have coeliac, you could be cutting out a food group unnecessarily). “Given the genetic component, it’s important to get formally diagnosed as it’s more likely to affect your family if you have it,” he says. “You also have to think about the long-term complications of the disease.”

He says: “If you suspect you might have coeliac, use Coeliac UK’s symptom checker and continue eating gluten until you go to your GP and get tested.”

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