Nearly half of women have experienced post-sex blues, QUT research has found.

Postcoital dysphoria (PCD), characterised by tearfulness, a sense of melancholy or depression, anxiety, agitation or aggression following sexual intercourse, had been experienced by 46 per cent of surveyed women at some point in their lives.

Among 230 female university students who completed an online survey, one in 20, or 5.1 per cent, had experienced PCD symptoms several times in the previous four weeks. Two per cent of women reported experiencing PCD symptoms "always" or "most of the time".

The study, led by Professor Robert Schweitzer from QUT's School - Psychology and Counselling, has been published in the Journal of Sexual Medicine.

"The findings build upon our previous research investigating the correlates of sexual functioning in women," Professor Schweitzer said.

"This is an area which is under-researched and the results may seem surprising because consensual sex is supposed to be an enjoyable experience.

"But the results of our original research in this area have now been confirmed in an international multinational study on negative postcoital emotions, which appear to have evolutionary functions."

Professor Schweitzer said there appeared to be no relationship between PCD and intimacy in close relationships and it could be difficult to pinpoint why some women experienced PCD.

"Overall our results support the notion that PCD symptoms are prevalent in the general population and that they can occur in spite of an otherwise physiologically functional sexual experience," he said.

"PCD is a multifactorial condition. A history of childhood sexual abuse was one predictor of PCD in our study.

"And it is also possible that those who have a tendency to become 'fused' with others may perceive the end of sexual intercourse as a separation from their partner, which may be overwhelming and cause PCD symptoms."

A previous study by Professor Schweitzer found one in three women had experienced PCD at some point.