Why do women look painful during orgasm?

Many people may have noticed in their married life that women have a painful expression when they reach orgasm. At this time, they get great pleasure physiologically, but why do they look painful?

Pleasure? Or pain? Orgasm and pain share common facial expressions. That's because the parts of the brain and spinal cord that control orgasm and pain overlap, and this close connection inevitably leads to some interesting consequences. For example, on the positive side, when women orgasm through vaginal self-stimulation, their sensitivity to pain is reduced by half compared to normal (resting) pain.

In some cases, when medication fails to relieve pain, surgery may be needed to cut certain spinal nerve pathways to achieve pain relief, thereby blocking the possibility of orgasm. Sometimes, the effectiveness of the surgery is temporary, with pain returning after 6 months, but the ability to orgasm also returns. At least two areas of the brain (the insular cortex and the anterior cingulate cortex) are consistently active during both orgasm and pain.

This raises an intriguing but as yet unanswered question: How exactly does the brain distinguish between pain and orgasmic pleasure? What are the differences between the neurons that produce the sensation of pain and the pleasurable sensations of orgasm? Do these two areas of the brain have some properties that are common to both pain and orgasm?

This allows emotional expressions of the same intensity (shown by the facial muscles) to be differentiated as different feelings of pain and orgasm. It is likely that the neural pathways that transmit pain and pleasure are closely parallel in the spinal cord and brainstem, so that both lead to the same response of arousal and facial expression muscles, and then the two sensations are distinguished somewhere in the brain and transmitted to the pain-sensitive cortex and the pleasure-sensitive cortex respectively. That way, sensory activity from the genitals or from other areas would cause the same changes in facial expression, before the brain ultimately distinguishes between them.