Research by the University of Hertfordshire has suggested that women's desire to hit the shops may be linked to hormonal changes during their menstrual cycle.
The most dangerous time to be wielding a credit card is, according to Professor Karen Pine, the ten days before a woman's period - the "luteal phase" - during which they're more likely to splash out as a way of handling the "negative emotions created by their hormonal changes", as the BBC puts it.
Pine quizzed 443 women aged between 18 and 50 about their spending habits. Nearly two-thirds of the 153 participants who were in the luteal phase "admitted they had bought something on an impulse and more than half said they had overspent by more than £25".
Chillingly, the BBC adds: "A handful of the women said they had overspent by more than £250."
Pine explained: "The spending behaviour tends to be a reaction to intense emotions. They are feeling stressed or depressed and are more likely to go shopping to cheer themselves up and using it to regulate their emotions."
She added: "We are getting surges and fluctuations in hormones which affect the part of the brain linked to emotions and inhibitory control. So the behaviour we found is not surprising."
Previous research has demonstrated another possible contributory cause for the lust for merchandise: Women like to buy things to make them themselves "feel more attractive" at the time of ovulation.
Pine's research indicated that most of the extra luteal phase money went on "adornment, including jewellery, make-up and high heels".
She elaborated: "Other researchers have found there is an ornamental effect around the time of ovulation."
Pine, who will present her findings later this week at a British Psychological Society shindig in Brighton, rather obviously concluded that the best way for women to avoid financial ruin was to "avoid going shopping in the week before their period was due".
Victims of "luteal phase bankruptcy syndrome" will be relieved to learn that many of Pine's subjects "felt remorse" after indulging in some not-so-light self-ornamentation.