SSI for premature babies

I found this article to be useful :
http://findarticles.com/p/articles/mi_qn4176/is_20060721/ai_n16671143

It says :
A newborn who weighs less than 1,200 grams (about 2 pounds, 10 ounces) can qualify for SSI on the basis of low birth weight, if otherwise eligible. A child who weighs between 1,200 and 2,000 grams at birth (about 4 pounds 6 ounces) and who is considered small for his or her gestational age may also qualify.