A researcher associated with the Catholic University of Louvain (UCL) in Brussels has accidentally captured the images showing the production of an egg inside a woman's body, something known as 'ovulation' in medical terminology.
Jacques Donnez has revealed that he captured the event while preparing to carry out a partial hysterectomy on a 45-year-old woman.
Observing ovulation in humans is extremely rare, and previous images have been fuzzy.
"The release of the oocyte from the ovary is a crucial event in human reproduction. These pictures are clearly important to better understand the mechanism," New Scientist magazine quoted Donnez as saying.
Most scientists believe that the release of an egg occurs as a sudden, explosive event.
However, Donnez's pictures show it taking place over a period of at least 15 minutes.
The researcher says that shortly before the egg is released, enzymes break down the tissue in the mature follicle, a fluid-filled sac on the surface of the ovary that contains the egg.
He says that this prompts the formation of a reddish protrusion, and after a while a hole appears, from which the egg emerges, surrounded by support cells.
Donnez says that it then enters a Fallopian tube, which carries it to the uterus.
He admits that there are no immediate medical implications from the pictures.
However, Australian researcher Darryl Russell, who researches reproductive health at the University of Adelaide, calls the images remarkable.
"In animals, even when we control hormone levels - allowing us to predict the time at which ovulation will occur - it is very rare to see it in progress," Russell says.
The images captured by Donnez will be published in Fertility and Sterility.