Endoscopic image of the human foetus in vivo, after 14 weeks, showing the umbilical cord, convoluted and pressing against the foetal stomach.The umbilicus supports 2 arteries carrying deoxygenated blood from the foetus, and 1 vein supplying oxygenated blood. The endoscope, a series of lenses and a fibre- optic light source, is inserted through the cervix (the neck of the womb) and manipulated until a "window" into the amniotic sac (which surrounds the embryo) is found (ie an area of the wall that is thinner).