Scientists at the University of Belfast say that not having an orgasm during sex can be harmful to health.

When not getting an orgasm the woman’s body undergoes serious stress. Arousal leads to increased levels of the hormone estrogen and the blood surges to the reproductive organs. During orgasm the stagnated blood is removed and the body is cleansed of pathogenic bacteria. This in turn can lead to diseases such as mastopathy or myoma due to stagnated blood.

Read more here.