There are lots of things to think about when booking a holiday and taking out travel insurance can end up falling down the list of priorities until the last minute.

If you're planning to go abroad - or you've already booked - then it's vital you get as soon as possible so you're covered both before and during your . Travel insurance is not just limited to the period that you are away, as it also covers you before you go. So by taking out a policy when you book, this means you will be in the event that something stops you from being able to travel, like with the chaos at Heathrow today but also if you have a health condition.

Travel insurance covers things like medical costs, repatriation, baggage and personal belongings, and cancellations if you can't travel, but it doesn't cover undeclared pre-existing medical conditions, so it's important to make sure you declare these when you take out a policy or you can risk invalidating your insurance.

But understanding what counts as a pre-existing medical condition can be complicated, particularly for women who take (HRT).

HRT is given to help relieve menopause symptoms and generally requires a prescription from a GP, but whether this then counts as a pre-existing medical condition women need to declare is somewhat of a murky area.

According to Aviva, a pre-existing condition is "when you've had symptoms, medication, advice, treatment, or tests for something before taking out health cover". In this case, HRT does appear to be a form of medication that you would need to declare, but Aviva told The Express that this isn't the case.

Aviva's spokesperson told The Express: "We consider the menopause to be a normal part of ageing and we do not require customers to disclose it to us. Likewise, if a customer is taking HRT solely for the menopause, it does not need to be declared.

"Our policies require customers to inform us of any diagnosed illness, disease, or injury for which they have been prescribed medication; received or are awaiting tests/investigations; been under or are still under a specialist, or have been admitted to hospital or had surgery."

Similarly, Admiral also says menopause - whether requiring HRT or not - is not considered a medical condition, so customers aren't required to declare this on their insurance.

A spokesperson for the firm told the Express: "This means that if it was identified at claim stage that the customer was experiencing menopause or taking HRT, it wouldn't invalidate their insurance and would have no impact on their claims settlement.

"Generally, we need to know about all medical conditions someone currently has. With some medical conditions, such as heart problems, we need to know if someone has ever been diagnosed with them, even if they have now recovered and are no longer being treated for these. At Admiral, we ask about these when someone gets a travel insurance quote.

"It is always best to include all medical conditions you've had or check with your insurer before you take out cover, if you're not sure."