Boing Boing has a helpful write-up of what, and how, infants in the womb know about the world. Here are two of the highlights:
"They can tell the difference between dim and very dim. That's what they'd see if mom removed outer clothing on a sunny day," said William Fifer, Ph.D., head of the fetal/infant development lab at Columbia University's division of developmental psychology."
And:
Turns out, babies suck harder on the pacifiers when they hear sounds that are familiar to them from before birth. Newborns prefer their mother's voice over anyone else's (even dad's). They prefer hearing phrases from books they were read while in the womb, compared to new stories. They're even already favoring one language over another.
They don't specify how old these infants are when these studies have been conducted. The eyes and ears are complex systems and don't come into being quite late.
But the article left out some of the most interesting aspects of prenatal development. Sean Gallagher points out that "reflex movement begins at around seven weeks, and grows in complexity in the 8th week." The movement of the infant in the womb is crucial for them to establish a sense of their motor capabilities, or what Gallagher calls their 'body schema.'
The body schema is the pre-reflective, non-cognitive functioning of the body in the world, and is crucial to the proper functioning of the human person, despite the fact that unlike our body images, it is hidden beneath the surface of our experience. Though Gallagher doesn't go this route, it's not implausible to suggest that the body schema is a type of embedded knowledge that the body has acquired through practice, practice which begins even before birth.