(Reuters Health) - Children born very prematurely today are more likely than those born years ago to survive without a serious disability, but they’re still at risk for developmental delays, according to a new study from France.

“We know medical practice and the organization of care have changed over the past 15 years,” said senior author Dr. Pierre-Yves Ancel, of the French National Institute of Health and Medical Research (INSERM) in Paris. “It’s important to examine whether the outcomes have changed.”

Smaller studies over past decades have showed improvements in outcomes of children born extremely premature, “but we haven’t been able to get a population study,” study co-author Dr. Andrei Morgan, who is also affiliated with INSERM, told Reuters Health.

Ancel and Morgan and colleagues used data collected nationally in France over two years, starting in March 2011, on 5,170 children born between 22 and 34 weeks gestation. A full-term pregnancy lasts 39 to 41 weeks.

About 52 percent of children born between 22 and 26 weeks gestation survived to age 2 years. That was true for 93 percent of babies born after 27 to 31 weeks gestation and for nearly 99 percent for those born at 32 to 34 weeks.

The risk of cerebral palsy decreased with longer gestation.

When the researchers compared their findings to data from a previous study started in 1997, they found that the proportion of extremely premature infants surviving to age 2 without moderate or severe disability had generally increased.

For babies born at 25 to 26 weeks, for example, the rate of survival without moderate or severe physical disabilities rose from about 46 percent in 1997 to about 62 percent in 2011.

But the premature infants born more recently were still at risk for developmental delays, such as problems with communication abilities, gross motor skills, fine motor skills, problem solving abilities and personal-social skills.

Rates of those problems were about 50 percent among babies born at 22 to 26 weeks, about 41 percent among those born at 27 to 31 weeks and about 36 percent in preemies born at 32 to 34 weeks, the researchers report in The BMJ.

“I think it’s also important and interesting to know that outcomes are improving, but there are children who remain at risk at higher gestational ages,” said Morgan.

The research team hopes to learn more about outcomes when the children are 5 and 10 years old, Ancel said.

“These results are important, but we need more information in the long term,” he said.

SOURCE: bit.ly/2vMTUZv The BMJ, online August 16, 2017.