Premature births, when a baby is born before 37 weeks,  affect about 10 percent of pregnancies, according to the CDC.
But when can a baby survive outside the womb and what are the biggest risks?

Premature births, when a baby is born before 37 weeks,  affect about 10 percent of pregnancies, according to the CDC.

But when can a baby survive outside the womb and what are the biggest risks?