Check out this iVillage article, researchers found that women's menstrual cycles can affect their shopping habits, along with changing their eating habits: http://www.ivillage.com/shopping-too-much-you-re-probably-ovulating/4-a-477194 
During the fertile phase of the women's menstrual cycles (roughly day eight to 15 of a 28-day cycle), the researchers found a significant increase in their focus on appearance. During their fertile days, women are also more likely to buy clothes, the study showed.
The study authors suggested that the explanation for this pattern of behavior can be traced back to women's evolutionary roots.
"In ancestral times, women had to focus more time on mating-related activities during the fertile phase of the menstrual cycle, when the likelihood of conception was highest," Saad explained in the news release. "Those same psychological and physiological mechanisms now lead women to engage in greater consumption of products relevant to reproductive drives during the fertile phase of their cycle."
Has anyone noticed that they spruce up a bit more or tend to get the shopping bug around ovulation time?