WASHINGTON—Labor is becoming less of a late-night surprise, but some hospitals are starting to tighten the rules for elective deliveries—because some babies are being delivered too early.

More hospitals are expected to crack down as regulators begin new quality measurements next spring that aim to reduce too-early elective inductions and first-time cesareans.

Induced labor is on the rise for lots of reasons, some medical and some not. But recent research shows a troubling link between elective inductions and these so-called late preemies. These aren’t the dire too-small babies that the word premature conjures, but near-term babies who nonetheless are at higher risk of breathing disorders and other problems than babies who finish their very last weeks in the womb.

“It was an ‘aha’ moment for me,” recalls Dr. Bryan Oshiro of his visit to a Utah intensive care nursery several years ago, where neonatologists pointed to babies there simply because they’d been induced too soon.

National guidelines from the American College of Obstetricians and Gynecologists have long discouraged elective deliveries before the 39th week of pregnancy. But some hospitals that took a close look were surprised. At Utah’s Intermountain Healthcare, for example, 28 percent of elective deliveries were breaking ACOG’s rule in 2001, Oshiro told a March of Dimes meeting on preventable prematurity this month.

Most were being induced in week 37. So Oshiro pulled the medical charts and found those near-term babies had more than double the risk of ending up in neonatal ICU, suffering respiratory distress, even needing a ventilator.

It took several years of policing. Inductions now are allowed only after meeting a checklist of requirements. But today only about 3 percent of Intermountain’s elective deliveries occur before 39 weeks—and infant hospitalizations have dropped, saving money, too, says Oshiro. Now a maternal-fetal medicine specialist at Loma Linda University in California, Oshiro is about to pilot a similar program at hospitals in that area.

“If there’s no need to intervene, please don’t intervene,” is Oshiro’s message.

Labor is induced in more than 1 in 5 births, double the rate in 1990, according to the Centers for Disease Control and Prevention. Many cases are for clear health reasons, such as a problem with the fetus or a sick mom or a pregnancy that has dragged well beyond the woman’s due date.