Ladies, the next time you helplessly indulge in a shopping spree, blame it on your ovulation cycle. Impulsive buys are not due to a lack of willpower or sales, they’re actually driven by your hormones wreaking havoc. According to a recent study to be published in the Journal of Consumer Research, women naturally seek more options in dating partners and a greater variety of products and services when they are most fertile.

Ovulation, or “the other time of the month” occurs in the third phase of a woman’s monthly cycle, which takes about 28 days. During the ovulatory phase (about day 14), one egg or follicle in the ovary emerges as the dominant one as it’s ready to drop. This causes a surge and peak in estrogen, which leads to an increase in sex drive, says the American Pregnancy Association.

The surge of hormones, in turn, increases the desire for new options in men. The rise in estrogen around ovulation can specifically influence a woman’s attitudes, preferences, and behaviors.

In an effort to explore the link between choices in women’s personal relationships and the marketplace, Kristina M. Durante, lead author of the study and University of Texas at San Antonio marketing assistant professor, and her colleagues conducted a series of four experiments. They recruited over 500 women between the ages 18 and 40, either single or married, who were not pregnant or taking hormonal contraceptives.

The findings revealed women’s desire for new options in men sparked a desire for greater variety in consumer products. Durante compares ovulating women to fishermen when it comes to giving yourself options.

"Just like a fisherman casting a wide net, ovulating women seek to cast a wide net into the dating pool and expand the number of potential suitors they have to choose from," she said in the press release. Durante added: "And, this desire for variety in men at ovulation triggers a variety-seeking mindset that carries over into desire for variety in products."

However, when researchers asked women to imagine themselves "in a loving relationship with a desirable partner," or when married subjects were asked to put on their wedding rings, these women no longer wanted greater variety when ovulating. Feeling loyalty to a romantic partner can mitigate the desire for product variety. This suggests loyalty in romantic relationships can translate to brand loyalty in the marketplace.

A similar 2010 study published in the Journal Consumer Research found when ovulating women do shop, they unconsciously buy sexier clothes. Unconsciously they dress to impress, but ironically, it’s not to impress men but to outdo rival women during their ovulation phase. The belief behind it is if you look more desirable than your competition, you are more likely to stand out to a desirable mate.

These findings have practical implications for marketers because a woman’s ovulation cycle can have a significant effect on her consumer behavior. A company could use marketing messages related to variety and novelty to allure fertile women to shop during their other time of the month. This warrants further research, however, into whether the social value, cost, or rewarding nature of the product influences ovulation’s effect on greater variety.

In the meantime, ladies, next time you break the bank at the mall, blame it on the ovulation cycle.

Sources: Arsena AR. and Durante KM. Playing the Field: The Effect of Fertility on Women’s Desire for Variety. Journal of Consumer Research. 2014.

Ambady N. Rosen KS, Rule NO, Slepian ML. Mating Interest Improves Women's Accuracy in Judging Male Sexual Orientation. Psychological Science. 2011.