The study has been conducted by researchers at University of Turku in Finland and has been published in the Royal Society journal Biology Letters.
The researchers found that women who have high levels of stress hormone cortisol were found to be less attractive, signaling lower reproduction potential as cortisol negatively affected their fertility.
"Interestingly, facial attractiveness correlated negatively with plasma cortisol level suggesting stress reduces attractiveness in women. This supports previous findings from male faces, which show cortisol is inversely related to facial attractiveness. This has been interpreted as a mediator of condition dependent cues in the face (e.g. to health) or as a signal of the ability to cope with stressors", lead researcher Dr Markus Rantala said.