Tiny baby Melinda Star Guido heading home

(CBS/AP) At birth, Melinda Star Guido weighed less than a can of soda - only 9 1/2 ounces. After spending close to the first five months of her life at the hospital, she's headed home.

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One of the world's smallest surviving babies, Melinda has been growing steadily and gaining weight since she was born premature at 24 weeks in August at the Los Angeles County-USC Medical Center. She is the world's third smallest baby and the second smallest in the U.S.

Now weighing 4 1/2 pounds, Melinda has made enough progress to be discharged, doctors say. It's too early to know how she will fare developmentally and physically, but doctors plan to monitor her for the next six years.

About 7,500 babies are born each year in the United States weighing less than 1 pound, and about 10 percent survive. Most babies as small as Melinda don't survive even with advanced medical care.

A study published in the journal Pediatrics in 2010 found that many survivors have ongoing health and learning concerns. Most also remain short and underweight for their age.

There are some rare success stories. The smallest surviving baby born weighing 9.2 ounces is now a healthy 7-year-old and another who weighed 9.9 ounces at birth is an honors college student studying psychology, according to doctors at Loyola University Medical Center in Illinois where the girls were born.

Soon after birth, Melinda was treated for an eye disorder that's common in premature babies and underwent surgery to close an artery. Melinda's mother, 22-year-old Haydee Ibarra, held her for the first time after the operation in November.

Despite the hurdles, doctors said Melinda was fortunate she did not suffer serious complications such as bleeding in the brain.