Board Thread:Warhammer 40k General Discussion/@comment-6078851-20140531013206/@comment-69.35.168.60-20140603191226

A womb is a pouch. A larvae is a completely different form of life, specifically because it is born of an egg. A humanoid womb needs a way to transfer the fluids into the growing organism. Diffusion is unlikely to work. Larvae aren't born from wombs. Ork are. Wombs need something to connect into the organism. The umbilical cord connects to the womb in order to transfer most materials. The Ork "wombs" are probably meant to resemble the wombs of other humanoids, given that they were engineered.

More importantly, the reason larvae and other short-term egg don't have umbilical cords because they are short-term, not because they are seperate from a host. The eggs thus have an extremely small amount of nutrients stored in the organism. Given that an Ork womb stays viable for years, the umbilical cord or equivalent is NECESSARY. There's almost no chance that Orks don't have them.

In summary, Larvae don't have umbilical cords because they are so short term, and thus no belly buttons. Longer-gestation beings NEED a way to feed the growing organism, so have some sort of connection to the "baby". Since Orks are one of the longest term gestations of humanoid wombs, they MUST have a way to transfer food to the Ork. So the bellybutton is almost certainly needed.