In this video, Justin from the Institute of Human Anatomy, shows a cross-section of the female reproductive system, and explains the basic mechanics of period cramps.

Other factors than what are mentioned in the video can also be at play, such as high levels of prostaglandins, uterine fibroids, endometriosis, abnormal uterus development, etc.

Who knew biology could be so complicated??

Clarification

Endometriosis is a complicated condition, and is deserving of a entire video in itself.

Despite affecting 176 million women worldwide, it’s origin and cause are still hotly debated, and poorly understood.

Several theories exist as to its origin and cause, but nothing is seen to be definitive. For those curious to learn more about the possible origins of this debilitating condition, feel free to browse through these recently published research papers.