For some young women sex leaves no afterglow and some even feel sad new research suggests. More than 200 young Australian women were quizzed on life between the sheets and one in three young women said they experienced post-coital blues at some point in their lives. Ten per cent said they frequently or almost always felt sad after making love.

Study author Robert Schweitzer, from the Queensland Institute of Technology said in a statement: 'Under normal circumstances, the resolution phase of sexual activity, or period just after sex, elicits sensations of well-being, along with psychological and physical relaxation.

'However, individuals who experience post-coital dysphoria (sadness) may express their immediate feelings after sexual intercourse in terms of melancholy, tearfulness, anxiety, irritability or feeling of restlessness.'More research is needed to see if Schweitzer's findings are the same in other age groups.

He said the cause of these feelings were unknown. One woman surveyed said that she feels 'melancholy' after sex, but said those feelings are disconnected from her feelings of love and affection for her partner.

Prior sexual abuse can cause feelings of shame, guilt and loss in later sexual encounters, Schweitzer said. However, his research, published in the quarterly International Journal of Sexual Health, found only a moderate correlation between prior sexual abuse and later post-sex let down.

He added: 'This suggests other factors, such as biological predisposition, may be more important.'The next step, Schweitzer said, is to look at women's emotional characteristics and how they view themselves to see if personality contributes to bedroom blues.