Scientists quizzed 230 sexually active women between the ages of 18 and 55 to support their theory. It emerged 46 per cent had experienced post-sex sadness at least once in their lives. One in 20 had even experienced it several times in the past four weeks.
It could be assumed high levels of intimacy with a sexual partner would lessen the symptoms, but no connection was found between intimacy and post-coital blues.
"The findings build upon our previous research investigating the correlates of sexual functioning in women," lead author Dr Robert Schweitzer of Queensland University of Technology explained.
"The results of our original research in this area have now been confirmed in an international multinational study on negative post-coital emotions, which appear to have evolutionary functions."
Previous research using twins showed genetics could play a part in the prevalence of negative post-sex emotions. It's also been suggested sufferers could have experienced sexual abuse in the past.
"It's plausible that women with an abusive history may be more prone to enter relationships in which they do not always feel in control of their experience, or assertive about their wants/needs, and perhaps may be prone to resentment," the researchers said.
Another group of women who may experience the symptoms more are those who find it hard to differentiate from others. After sex they could feel as though they are "separating" from their partners, causing an onslaught of negative emotions.
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