As if it wasn't bad enough that once a month women get plagued with stomach cramps, emotional ups and downs, and a desire to eat anything we see; we also seem to get headaches around our time of the month.
But why? Why is life such a cruel mistress?
New research suggests that women who frequently suffer from headaches have a noticeable lack of iron in their systems, thanks to all the blood that's lost during a period.
A group of neurologists carried out a study which assessed the medical records of 115 women who had gone to the doctor about their time-of-the-month headaches, and found that a hefty proportion of those who were medically diagnosed with migraines were also diagnosed with "end-menstrual migraines" which hit them just at the end of.
This led researchers to believe that the cause of these banging headaches was low levels of iron in patients' systems, which gives us the perfect excuse to go out an eat steak, because that's full of the iron we need around that time.
You can also get your top-up of iron in dark leafy vegetables such as spinach and kale, brown rice, cereals, fish and nuts and seeds. Er, and dark chocolate, because let's not forget the important one.
Follow Cat on Twitter.
This article originally appeared on Cosmopolitan.co.uk. Minor edits have been made by the Cosmo.ph editors.