The majority of babies born prematurely will make it to adulthood without any major health issues, according to new research.
In an extensive Scandinavian cohort study, researchers found there was a high prevalence of survival without any major comorbidities among those born prematurely, even though preterm births are known to be associated with cardiometabolic, respiratory and neuropsychiatric disorders in adulthood. There was an exception however. Outcomes were worse for those born extremely preterm (22-27 weeks).
The study is important, say its authors, as most previous research has concentrated on the negative consequences of the baby not making it to term. “Prior studies of long-term sequelae of preterm birth have focused almost entirely on specific adverse outcomes, either physical, mental or social … Potential positive outcomes or indicators of resilience have rarely been assessed,” they wrote recently in JAMA.
In this study, researchers looked at the records of more than 2.5 million people born in Sweden between 1973 and 1997 who had information about their gestational age and who had been followed up for survival and comorbidities until the end of 2015. So they were looking at a cohort of people who were aged between 18 and 43 at the end of the study.
They were checking to see how many of these people had developed the types of diseases that classically commence in early adulthood and tend to predict disability and mortality. These comorbidities included chronic pulmonary disease (including asthma, hypertension, diabetes, mental disorders, cerebral palsy and epilepsy (there were 19 in all). And importantly, they were looking to see if prematurity increased the risk of these diseases occurring.
So starting with the baseline finding that 63% of babies born at full-term made it to adulthood without developing any of these major comorbidities, researchers could compare this with outcomes of those born prematurely.
As you would expect, the closer to term the baby was born the better the outcome. So for babies born at 37-38 weeks, 61.2% were chronic disease free as adults and for those born 34-36 weeks 58% were healthy as young adults.
The odds start to shift for babies born earlier than 34 weeks, researchers found. So for those born at 28 to 33 weeks, less than half (48.5%) had no major comorbidities at adulthood and for those premmies born earlier than 28 weeks only 22.3% were chronic disease free when they were older.
But given that less than two-thirds of full-term babies were healthy as young adults, in general the prematurity (except when it was extreme) did not appear to be to confer a major detrimental effect on health outcomes, the study authors suggested.
“The relatively high prevalence of this outcome reflects not only the treatment advances that have occurred over the past 50 years, but also the apparent resilience of preterm survivors in maintaining good health,” they said.
Of course, the story is very different for those babies born very prematurely, especially those born before 28 weeks, who, the researchers say, face significantly greater long-term challenges. For these children, more attention and research is needed.
“Additional studies are needed to identify protective factors across the life course that enhance resilience and the long-term health trajectory of persons born prematurely, particularly at the earliest gestational ages, the researchers concluded.
JAMA 2019;322(16): 1580-1588. Doi:10.1001/jama.2019.15040