TUESDAY, Oct. 22, 2019 (HealthDay News) -- Having a premature baby can be frightening for parents, but new research delivers a calming finding: Many premature babies end up as healthy adults without major illnesses.
The study of more than 2.5 million children found that more than half of those born prematurely had no major medical concerns in adulthood.
"Preterm birth has been linked with higher long-term risks of several health problems, including heart, lung, neurological and mental disorders," said study lead author Dr. Casey Crump, vice chair for research in the Department of Family Medicine and Community Health at the Icahn School of Medicine at Mount Sinai in New York City.
But, he noted, past studies have focused almost entirely on those negative outcomes.
"There were no studies that we know of that looked at good health in premature births into adulthood. These findings matter for the growing number of people born prematurely because they show that most can lead a healthy, resilient life with good overall function in adulthood," Crump said.
Unfortunately, the picture isn't as rosy for those babies born extremely prematurely (22 to 27 weeks). Just 22% of these preemies in the study had no major health conditions in adulthood. By comparison, the study found that 63% of people born at full-term had no major health issues as an adult.
Preterm birth is one that occurs before 37 completed weeks of a pregnancy. Very preterm is 28 to 33 weeks, late preterm is 34 to 36 weeks, early term is 37 to 38 weeks and full-term is 39 to 41 weeks.
"The third trimester of pregnancy is a critical period for fetal growth. Preterm birth interrupts normal growth and maturation of all fetal organs, which can alter their structure and function," Crump said. He added that those changes can set up a susceptibility to chronic health conditions later in life.
Nearly 11% of babies born worldwide are born prematurely, the study authors said. About 95% of these underdeveloped babies now survive into adulthood because of advances in medical care.
The latest study looked at data collected in Sweden on births between 1973 and 1997. Nearly 6% were born prematurely.
Preterm infants were more likely than full-term infants to be male, multiple births, or first-born children. Their mothers were more likely to be at the extremes of age for pregnancy. Moms of premature infants were also more like to smoke and have other health conditions such as high blood pressure in pregnancy or diabetes.
The researchers looked at the health of the children when they were between 18 and 43. Some of the conditions the researchers looked for in adulthood that have previously been linked to premature birth included asthma, high blood pressure, diabetes, kidney disease, mental conditions, cerebral palsy and epilepsy.
Crump suggested that people born prematurely may improve their long-term health by following a healthy lifestyle throughout their lives, including regular physical activity, a healthy diet, maintaining a normal weight and avoiding smoking and substance abuse. He said continuing preventive medical care is also important throughout their lives.
Dr. Deborah Campbell is director of neonatology at the Children's Hospital at Montefiore in New York City. She said these findings are further confirmation of what's been reported over time. "In general, the vast majority of individuals born preterm won't be severely impacted or disabled. Overall, most will be functioning and contributing adults," said Campbell, who was not part of the study.
Like Crump, Campbell expressed concern for the youngest of the premature infants. She said that before 25 weeks of gestation is just a very vulnerable period of time for a developing fetus, and though doctors have been trying for years, "we can't replicate the womb," she explained.
Campbell said that while advances in care have helped babies survive, it's also important to focus on care for pregnant moms. She said improving the health of expectant moms will help improve the health of babies.
The findings were published Oct. 22 in the Journal of the American Medical Association.
Learn more about premature birth from the U.S. Centers for Disease Control and Prevention.