According to a new report, boys are far more likely than girls to be born early—and have a much harder time after birth, too.
"This is a double whammy for boys," said research leader Dr. Joy Lawn of the London School of Hygiene & Tropical Medicine."It's a pattern that happens all over the world."
While the gender gap isn't huge (boys made up around 55 percent of preterm births in 2010), experts are still scratching their heads as to why it happens.
One theory? Moms have a higher risk of pregnancy complications like placenta previa and high blood pressure when carrying boys, which may be why they're linked to more preemie births.
But Lawn adds that if a preemie boy and a preemie girl are born at the same gestational age, the boy faces a much higher risk of death or disability. Just how much greater that risk is, though, is not yet known.
"Girls walk sooner than boys," Lawn told the Associated Press. "They talk sooner than boys. They develop more quickly. That's also true in utero." For a baby born prematurely, she said, "the difference of a few days maturity between a boy and a girl can mean the difference between major lung complications or not."
Researchers uncovered the stats after scouring through international records as part of a worldwide report on newborn health and prematurity. The release of the results was aptly timed, too, coming out right before World Prematurity Day on November 17.
But the gender divide isn't the only startling fact the study sought to highlight. Though it's hard to wrap your mind around it, a staggering 15 million babies are born too soon around the world. And while we're always talking about the U.S. preemie rate here at home, our rates have nothing on Africa and parts of Asia—where preemie rates are much higher, and babies have far fewer chances of surviving. Tragically, this is why 1 million babies die each year as a direct result of preterm birth. Another million die of conditions that are compounded by a baby's prematurity.
The report also looked at just how many preemies survive, but go on to suffer disabilities. Lawn noted that about 7 percent of survivors suffer from extreme neurologic developmental impairment, diagnosed with disorders like cerebral palsy, vision loss and learning disabilities.
But for those babies born before 28 weeks, they face the greatest risks and the biggest challenges of all. Fifty-two percent of these babies are estimated to have some degree of neurodevelopmental impairment worldwide.