...STILL A MYSTERY!!!!
How big is your baby at 17 weeks pregnant? About five inches long and more than three and a half ounces — the size of your open hand. (Open the other one too and imagine your baby cradled in both your arms right after delivery!) Body fat (baby's, that is) is beginning to form and will continue to accumulate through the end of your pregnancy. By the time your baby is born, body fat will make up about two-thirds of his or her weight (and will make all those chubby parts especially yummy).
Your baby is almost certainly listening up by now. In fact, loud noises — the dog barking, the doorbell ringing — will actually startle your baby (and also get him or her used to such noises; for instance, fetuses who regularly hear a dog barking will become babies who sleep right through Fido's outbursts). Your baby's eyes (which have fortunately finished their migration to the front of his or her head) are making small side-to-side movements and can even perceive some light, though the eyelids are still sealed. And since practice makes perfect, your baby is sharpening his or her sucking and swallowing skills in preparation for that first (and second…and third) suckle at your breast or bottle. In fact, most of the survival reflexes that your baby will have at birth are being perfected in utero right now.
And here's some proof that your baby is truly one of a kind (as if you needed any!). Within the next week or so, the pads on your baby's fingertips and toes will become adorned with completely individual swirls and creases (aka fingerprints).