For nearly 60 years, women have been taking the birth control pill for various reasons - mainly to avoid unwanted pregnancy, but also to control skin, period and hormone issues.
Even non-pill users probably know the layout of that little blister pack: 21 active pills, and seven non-active sugar pills which trigger "withdrawal bleeding" every month.
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But it turns out there's no medical reason for having a simulated period every three weeks, and this week the British healthcare system is changing its guidelines to reflect that.
Reportedly, one of the men who invented the pill devised the 'break' in order to please one particular man.
According to The Atlantic's Jonathan Eig - who has written extensively on the history of the pill - obstetrician, gynaecologist and devout catholic John Rock thought using sugar pills to mimic a women's natural cycle might get the pill past the Catholic Church and Pope John XXIII.
But it was no use - in 1968, Pope Paul VI declared all forms of artificial contraception to be against church doctrine. However, by then, the pill had already become available on the market, and so the 'break' became the standard.
The Independent reports that the NHS has updated their guidelines this week, advising British women that there's no medical reason not to take the contraceptive pill every day of the month.
"It should be made clear to women that this bleed does not represent physiological menstruation and that it has no health benefit," the new guidelines state.
Dr Diana Mansour, vice president for clinical quality at the Faculty of Sexual and Reproductive Healthcare, told the Telegraph she would recommend women take active contraceptive pills every day of every month.
"The guideline suggests that by taking fewer hormone-free intervals - or shortening them to four days - it's possible that women could reduce the risk of getting pregnant on combined hormonal contraception," she said.
So if you're dutifully taking your sugar pills every month, there's really no need - unless you're doing it out of some residual Catholic guilt.