LOS ANGELES -
Little Marielle Mirabelli is a happy, playful 8-month-old. But her life got off to a scary start. Her mother, Rita, suddenly went into labor two months early.
"I was terrified," said Rita Mirabelli, 27. "Will my baby survive? Will my baby have health problems? You go down and you see your baby in this contraption with tubes and with monitors."
Marielle is one of half a million premature babies born in the U.S. each year. A new report shows the U.S. has one of the worst preterm birth rates in the world; 12 percent-- the same rate as Thailand, Turkey and Somalia.
Experts say one reason is that mothers here have children later in life, which leads to multiple pregnancies that result in early deliveries. But many preterm births, like the Mirabellis, are a mystery.
"We don't know-- perhaps 50 percent of preterm births-- we don't really truly know the explanation," said Dr. Joe Leigh Simpson of the March of Dimes.
The report defines preterm as any time before 37 weeks. The earlier the baby is delivered, the greater the chance he or she will suffer lifelong health problems.
"The main issues are brain development and lung development," Simpson said.
Marielle is the average weight and height for her age, but she's still about two months behind developmentally.
"I know her risk of having learning disabilities, of having developmental delays are much higher than the average child," Rita Mirabelli said.
But her mom is hopeful she will catch up.
According to the study, 15 million babies are born preterm each year worldwide. Of those, about 1 million don't survive.
