It turns out that there are several ways our hormones can exacerbate hay fever symptoms – with oestrogen being the prime culprit.

As well as promoting ovulation and preparing the uterus for pregnancy, oestrogen is also thought to play an important role in immune system regulation alongside progesterone. This means that when our immune system identifies a pathogen, oestrogen is there to ramp up the inflammatory response, while progesterone tones it down. The two balance each other out, ensuring the response is proportionate.

But when our hormone levels fluctuate, that ability to control the response changes. Low levels of oestrogen mean we’re more susceptible to diseases (during the coronavirus pandemic, for example, researchers from the Zoe app noted a link between oestrogen and immunity to Covid-19), as progesterone’s impact on the immune system is unopposed. But having high levels of oestrogen can also cause issues.

“Peaks in oestrogen levels that typically occur in the days leading up to ovulation – during week two of your cycle – can make your immune system more sensitive to allergens, causing a more noticeable reaction,” Dr Duffy says. In hay fever terms, this might mean your symptoms are worse from one week to the next, even if the pollen levels stay the same – your body is simply reacting more severely.

Are your hormones making your hay fever worse? A doctor explains the link