This incredible photo beautifully displays a true knot. A true knot although rare, happens in roughly 0.3-2.2% of all births, can occur with active babies as they flip and turn in utero creating a knot within their umbilical cord. Although it can at times be of great concern with very close monitoring if detected it is more often well protected thanks to Wharton's Jelly a gelatinous mucous tissue. This acts as a moveable part of the umbilical which allows the knot to move up and down decreasing its ability to tighten. Adding to its wonder Wharton's Jelly will also harden once exposed to oxygenated air after birth tightening itself around the vein/arteries of the cord essentially clamping itself if left undisturbed. The birthing body is nothing short of miraculous.