Check out this awesome article on pre-natal sensory development:
Across the animal kingdom, senses come online in a very specific order that doesn’t vary much from one vertebrate to another. The first sense fetuses experience is touch. Then come the chemical-based senses—taste and smell. The ability to hear develops fourth. And finally, so late that many animals are born lacking it, comes sight.
Humans, with our relatively long gestation periods, are one of the few species that can see before we’re born. Not that there’s very much to see. The short answer to jackie31337’s question is, “Yes. It is, in fact, rather dark in there.”
“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.
Scientists have watched fetuses on ultrasound turn their heads away from bright lights held up to their mother’s stomach, Fifer said. And they’ve seen the brain waves of premature infants spike in response to a flash of light, or a change in visual stimulus—switching a card from vertical stripes to horizontal, for instance. Sight isn’t much of a sense at this point, but it’s enough.
Enough for what? That’s where things get interesting. See, senses don’t work via some neurological “off/on” switch. It’s more like building muscle. You have to exercise to get results. The more you work out the new sense, the more neuron connections are formed and the sense improves. But if you don’t use it, you lose it. Literally.
Amazing. The article goes on to discuss how studying fetal senses has helped doctors better care for pre-mature babies: Read more. Notice, in the first paragraph quoted here, that the author says that touch is the first sense that fetuses experience. And, yet, we’re still having arguments about whether or not there is even a chance that an unborn child can feel pain when it’s being burned to death with saline, having its limbs torn apart or its brains sucked out.