Smile ...

... you're on camera.

Observing ovulation in humans is extremely rare, and previous images have been fuzzy. Donnez captured the event by accident while preparing to carry out a partial hysterectomy on a 45-year-old woman. The release of an egg was considered a sudden, explosive event, but his pictures, to be published in Fertility and Sterility, show it taking place over a period of at least 15 minutes.

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. This prompts the formation of a reddish protrusion, and after a while a hole appears, from which the egg emerges, surrounded by support cells. It then enters a Fallopian tube, which carries it to the uterus.