The care of preemies now is SO different than it was years ago. Back then, people didn't think it was a good idea to hold preemies because of germs and stuff. Now, kangaroo care (skin to skin contact) is recommended, even for the smallest babies. My niece was 13.5 ounces when she was born 10 years ago, and her parents were allowed to touch her (obviously not to hold her for quite a long time because she was SO small).
It's hard to learn to attach to someone if during those crucial first months, you are not allowed to