Long-term health outcomes of preterm birtha narrative review

Faith Gette, Sumera Aziz Ali, Matthew Ho, Lindsay L. Richter, Edmond S. Chan et al. (+14)•View original

OverviewBalancedfable voice

Let's start with scale, because it sets the stakes. Preterm birth means arriving before 37 weeks, and the degree matters: the earlier the birth, the steeper the risks. In 2020, about 13.4 million babies were born preterm, roughly one in ten births worldwide. The burden isn't evenly spread. Southern Asia and sub-Saharan Africa account for about 65 percent of all preterm births, with places like Bangladesh reaching rates near 16 percent, compared with around 10 percent in the United States. That's not a small gap. It's a different starting line. Here's the paradox of progress. Neonatal care has improved significantly—respiratory support, surfactant, infection control—and global deaths linked to prematurity fell by nearly half between 1990 and 2019, from about 1.27 million to 0.66 million. But that's not the end of the story. In some regions, especially Southern sub-Saharan Africa, mortality hasn't dropped, and everywhere else, survival has shifted the problem from early death to lifelong morbidity. Families and systems feel this shift. In the United States, preterm birth cost about 25 billion dollars in 2016, or roughly 65,000 dollars more per child than term births, and a United Kingdom model estimated around 35,000 dollars in added costs per child up to age 18. Programs like Canada's EPIQ-3 try to bend those curves through quality improvement, but the signal is clear: early differences reverberate for decades. So what's happening under the hood? Gette and colleagues pull together a picture of a brain interrupted. The third trimester is prime time for cortical growth and wiring. When birth cuts that process short, vulnerable cell types—especially oligodendrocyte precursors that pre-myelinate white matter—face oxidative stress, inflammation, and intermittent low oxygen. That mix can leave behind white-matter injury and a brain that matures off-tempo: smaller volumes, thinner cortex, altered connectivity. Inflammatory cues matter too. Pro-inflammatory cytokines like interleukin-6, interleukin-8, and interleukin-1 beta surge in some preterm infants; interleukin-6 has been linked to autism risk, and interleukin-1 beta can damage neurons. Biology is setting the stage early. On that stage, outcomes fall along a spectrum. Cerebral palsy sits at the most visible end, and risk tracks tightly with gestational age. Among people born extremely preterm, about 10 percent to 20 percent develop cerebral palsy; in a French population sample, the rate was 12.4 percent at 24 to 26 weeks, dropping to 2.4 percent at 32 to 34 weeks. Across studies, preterm birth roughly triples the odds of cerebral palsy compared with term birth. But most survivors don't have major motor impairments, and yet many face quieter cognitive and behavioral hurdles. Average intelligence quotient scores run about 11 to 13 points lower for very preterm, very low-birthweight groups. Executive function, working memory, visuomotor integration, and self-regulation—these are the gears of learning, and they slip more often. The risk of epilepsy rises too, roughly one-and-a-half to four-and-a-half times depending on cohort, and rates of attention-deficit hyperactivity disorder and autism spectrum disorder are higher, especially after the most premature births. Senses carry their own load. Hearing problems range from mild loss to deafness requiring a cochlear implant. Visual issues show up as myopia, reduced acuity, strabismus, altered depth perception, and retinal complications. Many preterm children have sensory processing differences—too much input feels overwhelming, while too little input doesn't register. In a classroom, that looks like effortful listening, fatigue, and distractibility. It's not a lack of will. It's a nervous system trying to make sense of signals it wasn't quite ready for. The trajectory doesn't end at school. In adulthood, psychiatric risk ticks up. In a large national study, being born before 32 weeks nearly doubled and a half the hazard for psychotic disorders, and prescriptions for antipsychotics were about three times more common after extreme prematurity. That heterogeneity matters—outcomes worsen as gestational age at birth decreases and are shaped by environment—but the slope is consistent. The case Gette and colleagues make is simple: keep eyes on cognition, behavior, and senses across the lifespan, not just the first years. Breath is health, and the lungs remember. Across countries and study designs, preterm birth is linked to more asthma. In a United States sample of children, the odds were about 1.6 times higher for those born preterm. As those children age, the gap often widens. Norwegian adults born extremely preterm reported asthma at 35.6 percent, compared with 6.7 percent in term-born peers, and Swedish data showed more than double the rate of asthma medication prescriptions in young adults who were extremely preterm. A pooled analysis in European children put the overall asthma odds around 1.4 times higher. Sleep-disordered breathing, which fragments rest and stresses the cardiovascular system, is also more common—over 40 percent higher risk across childhood into mid-adulthood, and more than doubled in some adult extremely preterm cohorts. It isn't just symptoms; it's structure and function. Australian preterm school-age children showed a striking pattern: obstructed airways, hyperinflation, lower forced expiratory volumes, and computed tomography changes in about 92 percent of cases. Norwegian adolescents born extremely preterm had similar airway obstruction, especially if they'd had bronchopulmonary dysplasia, the chronic lung condition of prematurity. And bronchopulmonary dysplasia brings its own complications: about one in four children with moderate-to-severe disease develops pulmonary hypertension, a rise in pressure on the right side of the heart that's tied to poorer growth and neurodevelopment. You can feel how this loops back to everything else—exercise tolerance, school attendance, even attention. Cardiovascular risks shade in next. Blood pressure runs a little higher after preterm birth, and small differences compound over time. Meta-analyses suggest that in adulthood, systolic blood pressure is about 3.4 millimeters of mercury higher, with a modest rise in diastolic pressure too. On the heavier end of the spectrum, ischemic heart disease risk rises—hazard ratios approaching two in some groups—and heart failure risk climbs steeply with earlier gestational age: roughly three-and-a-half times higher for those born at 28 to 31 weeks and about four-and-three-quarters for 22 to 27 weeks. Each added week of gestation seems to lower lipid-disorder risk a bit as well, hinting at how much vessel biology is laid down before birth. Kidneys tell a story about endowment. We make most of our nephrons—the tiny filters that clean blood—late in pregnancy. Cut that short, and you start life with fewer filters and smaller kidneys. Acute kidney injury is common in the tiniest neonates; in one multi-center dataset, nearly half of all acute kidney injuries occurred in babies born between 22 and 29 weeks. The PENUT cohort, which followed extremely preterm infants, saw acute kidney injury rates drop as gestational age rose—from about 28 percent at 24 weeks down to roughly 9 percent at 27. That's a steep gradient over just a few weeks. It also sets up a long tail. Over that tail, chronic kidney disease risk looks about doubled when you track preterm survivors from childhood into mid-adulthood. The increase is strongest in those born extremely preterm—around 2.4 times higher—compared with a more modest bump, about 1.3 times, in other preterm groups. Early signs often show up in childhood as tiny amounts of protein in the urine and smaller renal volumes. Later on, those kidneys partner with slightly higher blood pressures to push cardiovascular risk again. The gut is a little messier to summarize. Prematurity is linked to early feeding difficulties and altered gut microbiota, and hospitalizations for digestive problems are more frequent. For specific diseases, signals vary by study. Some cohorts report higher risks of inflammatory bowel disease—odds ratios around 1.5 for Crohn's disease and 1.3 for ulcerative colitis—while others see no clear link. Esophagitis is an outlier: in younger children who were preterm, one study estimated an odds ratio near 6.8, but by adulthood that excess seemed to fade. In contrast, hernias show a clearer association. The through-line is heterogeneity, not uniform vulnerability. Growth is its own chess game. Some preterm groups lag in final height; others catch up. A recurring pattern is slower progress toward one's genetic height potential, particularly among those born appropriate for gestational age. Adiposity, though, moves more predictably. Systematic reviews suggest that preterm survivors have about a 19 percent higher odds of obesity. And the first year matters a lot: rapid weight gain in infancy more than doubles the odds of obesity by ages eight to eleven. That's a window for prevention. Breastfeeding appears to tilt the balance in a protective direction. Endocrine and metabolic programming weave through all of this. Thyroid function is a clear example. In term infants, thyroid hormones surge after birth; in very preterm infants they don't, a pattern called hypothyroxinemia of prematurity—low T3 and T4 without the big thyroid-stimulating hormone spike you see in congenital hypothyroidism. In babies born before 28 weeks, T3 and T4 often only reach term-like peaks two to three weeks later. Some of that normalizes, but not all. In one series, nearly one-fifth of infants born before 32 weeks ended up on levothyroxine, and maternal hypertension heightened that risk. A Swedish cohort followed into young adulthood found a 1.60-fold higher rate of medically treated hypothyroidism after extreme prematurity. Strikingly, about half of those treated had normal newborn screens, a reminder that a single test in the nursery can miss a moving target. The pancreas tells a parallel story. Beta cells, which make insulin, multiply mostly in the third trimester. Cut that short, and both insulin levels and later diabetes risk shift. A meta-analysis pooling about 2.2 million people estimated that preterm birth raises type 1 diabetes odds by about 20 percent and type 2 by roughly 51 percent. A massive Swedish cohort reported similar findings across the life course, with the type 2 signal especially strong in adult women. The type 1 pattern is nuanced—late-preterm and early-term births see a 10 percent to 20 percent higher risk, whereas the very earliest births sometimes showed lower risk—underscoring that biology doesn't always move in a straight line. Cancer and immunity round out the edges. Several studies point to elevated risks for hepatoblastoma and acute myeloid leukemia in children born preterm, though estimates vary by cancer type and region. Findings on allergies are inconsistent. Genetics and epigenetics are part of the backdrop—genome-wide studies have flagged variants tied to gestational timing, and DNA methylation patterns can carry signatures of early birth for years. There's an intergenerational echo too: women born preterm are more likely to deliver preterm themselves. Whether those signals directly drive later multisystem disease is still an open question. All of this lands in real lives. Educational supports are needed more often, not just for motor challenges but for attention, working memory, language, and sensory integration. German adolescents born extremely preterm reported more psychological difficulties and lower health-related quality of life, which shows up in peer relationships and classroom behavior. Health service use tells the same story: more specialized outpatient care, more school-based supports, and more touchpoints with systems that often aren't designed to talk to each other. And as babies become adults, participation and independence are on the line. Norwegian longitudinal data linked extreme prematurity with higher reliance on disability pensions in adulthood. Large Swedish studies documented higher rates of antihypertensive use, ischemic heart disease, heart failure, and chronic kidney disease across the lifespan after preterm birth. These aren't isolated events; they're the downstream of early cardiometabolic and neurodevelopmental trajectories. The practical takeaway from Gette and colleagues is straightforward: build structured transitions from pediatric to adult care, and keep surveillance going for cardiovascular, metabolic, renal, and mental health comorbidities. So where does that leave us? First, with pattern and nuance. Risks rise as gestational age falls, but there's real heterogeneity. Many preterm survivors thrive; some need targeted, time-sensitive help. Second, with agency. Proactive monitoring works best when it's holistic—hearing and vision screens, school supports, neurodevelopmental check-ins, and monitoring of blood pressure and kidney health, thyroid and glucose over time. Families ask for continuity; systems should make it the default. Finally, with a research agenda that's refreshingly concrete. We need larger, harmonized, longitudinal cohorts that follow people from the neonatal unit into midlife, across organs and outcomes. We need to tighten the links between early biological signals—like cytokines, lung imaging, kidney injury—and later disease. Not because we don't know enough to act, but because precise timing and targeted interventions could shift arcs that begin before the first birthday and trace through a lifetime.

The burden isn't evenly spread. Southern Asia and sub-Saharan Africa account for about 65 percent of all preterm births, with places like Bangladesh reaching rates near 16 percent, compared with around 10 percent in the United States. That's not a small gap. It's a different starting line.

Here's the paradox of progress. Neonatal care has improved significantly—respiratory support, surfactant, infection control—and global deaths linked to prematurity fell by nearly half between 1990 and 2019, from about 1.27 million to 0.66 million. But that's not the end of the story.

In some regions, especially Southern sub-Saharan Africa, mortality hasn't dropped, and everywhere else, survival has shifted the problem from early death to lifelong morbidity. Families and systems feel this shift. In the United States, preterm birth cost about 25 billion dollars in 2016, or roughly 65,000 dollars more per child than term births, and a United Kingdom model estimated around 35,000 dollars in added costs per child up to age 18.

Programs like Canada's EPIQ-3 try to bend those curves through quality improvement, but the signal is clear: early differences reverberate for decades.

So what's happening under the hood? Gette and colleagues pull together a picture of a brain interrupted. The third trimester is prime time for cortical growth and wiring.

When birth cuts that process short, vulnerable cell types—especially oligodendrocyte precursors that pre-myelinate white matter—face oxidative stress, inflammation, and intermittent low oxygen. That mix can leave behind white-matter injury and a brain that matures off-tempo: smaller volumes, thinner cortex, altered connectivity. Inflammatory cues matter too.

Pro-inflammatory cytokines like interleukin-6, interleukin-8, and interleukin-1 beta surge in some preterm infants; interleukin-6 has been linked to autism risk, and interleukin-1 beta can damage neurons. Biology is setting the stage early.

On that stage, outcomes fall along a spectrum. Cerebral palsy sits at the most visible end, and risk tracks tightly with gestational age. Among people born extremely preterm, about 10 percent to 20 percent develop cerebral palsy; in a French population sample, the rate was 12.4 percent at 24 to 26 weeks, dropping to 2.4 percent at 32 to 34 weeks.

Across studies, preterm birth roughly triples the odds of cerebral palsy compared with term birth. But most survivors don't have major motor impairments, and yet many face quieter cognitive and behavioral hurdles. Average intelligence quotient scores run about 11 to 13 points lower for very preterm, very low-birthweight groups.

Executive function, working memory, visuomotor integration, and self-regulation—these are the gears of learning, and they slip more often. The risk of epilepsy rises too, roughly one-and-a-half to four-and-a-half times depending on cohort, and rates of attention-deficit hyperactivity disorder and autism spectrum disorder are higher, especially after the most premature births.

Senses carry their own load. Hearing problems range from mild loss to deafness requiring a cochlear implant. Visual issues show up as myopia, reduced acuity, strabismus, altered depth perception, and retinal complications.

Many preterm children have sensory processing differences—too much input feels overwhelming, while too little input doesn't register. In a classroom, that looks like effortful listening, fatigue, and distractibility. It's not a lack of will.

It's a nervous system trying to make sense of signals it wasn't quite ready for.

The trajectory doesn't end at school. In adulthood, psychiatric risk ticks up. In a large national study, being born before 32 weeks nearly doubled and a half the hazard for psychotic disorders, and prescriptions for antipsychotics were about three times more common after extreme prematurity.

That heterogeneity matters—outcomes worsen as gestational age at birth decreases and are shaped by environment—but the slope is consistent. The case Gette and colleagues make is simple: keep eyes on cognition, behavior, and senses across the lifespan, not just the first years.

Breath is health, and the lungs remember. Across countries and study designs, preterm birth is linked to more asthma. In a United States sample of children, the odds were about 1.6 times higher for those born preterm.

As those children age, the gap often widens. Norwegian adults born extremely preterm reported asthma at 35.6 percent, compared with 6.7 percent in term-born peers, and Swedish data showed more than double the rate of asthma medication prescriptions in young adults who were extremely preterm. A pooled analysis in European children put the overall asthma odds around 1.4 times higher.

Sleep-disordered breathing, which fragments rest and stresses the cardiovascular system, is also more common—over 40 percent higher risk across childhood into mid-adulthood, and more than doubled in some adult extremely preterm cohorts.

It isn't just symptoms; it's structure and function. Australian preterm school-age children showed a striking pattern: obstructed airways, hyperinflation, lower forced expiratory volumes, and computed tomography changes in about 92 percent of cases. Norwegian adolescents born extremely preterm had similar airway obstruction, especially if they'd had bronchopulmonary dysplasia, the chronic lung condition of prematurity.

And bronchopulmonary dysplasia brings its own complications: about one in four children with moderate-to-severe disease develops pulmonary hypertension, a rise in pressure on the right side of the heart that's tied to poorer growth and neurodevelopment. You can feel how this loops back to everything else—exercise tolerance, school attendance, even attention.

Cardiovascular risks shade in next. Blood pressure runs a little higher after preterm birth, and small differences compound over time. Meta-analyses suggest that in adulthood, systolic blood pressure is about 3.4 millimeters of mercury higher, with a modest rise in diastolic pressure too.

On the heavier end of the spectrum, ischemic heart disease risk rises—hazard ratios approaching two in some groups—and heart failure risk climbs steeply with earlier gestational age: roughly three-and-a-half times higher for those born at 28 to 31 weeks and about four-and-three-quarters for 22 to 27 weeks. Each added week of gestation seems to lower lipid-disorder risk a bit as well, hinting at how much vessel biology is laid down before birth.

Kidneys tell a story about endowment. We make most of our nephrons—the tiny filters that clean blood—late in pregnancy. Cut that short, and you start life with fewer filters and smaller kidneys.

Acute kidney injury is common in the tiniest neonates; in one multi-center dataset, nearly half of all acute kidney injuries occurred in babies born between 22 and 29 weeks. The PENUT cohort, which followed extremely preterm infants, saw acute kidney injury rates drop as gestational age rose—from about 28 percent at 24 weeks down to roughly 9 percent at 27. That's a steep gradient over just a few weeks. It also sets up a long tail.

Over that tail, chronic kidney disease risk looks about doubled when you track preterm survivors from childhood into mid-adulthood. The increase is strongest in those born extremely preterm—around 2.4 times higher—compared with a more modest bump, about 1.3 times, in other preterm groups. Early signs often show up in childhood as tiny amounts of protein in the urine and smaller renal volumes.

Later on, those kidneys partner with slightly higher blood pressures to push cardiovascular risk again.

The gut is a little messier to summarize. Prematurity is linked to early feeding difficulties and altered gut microbiota, and hospitalizations for digestive problems are more frequent. For specific diseases, signals vary by study.

Some cohorts report higher risks of inflammatory bowel disease—odds ratios around 1.5 for Crohn's disease and 1.3 for ulcerative colitis—while others see no clear link. Esophagitis is an outlier: in younger children who were preterm, one study estimated an odds ratio near 6.8, but by adulthood that excess seemed to fade. In contrast, hernias show a clearer association. The through-line is heterogeneity, not uniform vulnerability.

Growth is its own chess game. Some preterm groups lag in final height; others catch up. A recurring pattern is slower progress toward one's genetic height potential, particularly among those born appropriate for gestational age.

Adiposity, though, moves more predictably. Systematic reviews suggest that preterm survivors have about a 19 percent higher odds of obesity. And the first year matters a lot: rapid weight gain in infancy more than doubles the odds of obesity by ages eight to eleven.

That's a window for prevention. Breastfeeding appears to tilt the balance in a protective direction.

Endocrine and metabolic programming weave through all of this. Thyroid function is a clear example. In term infants, thyroid hormones surge after birth; in very preterm infants they don't, a pattern called hypothyroxinemia of prematurity—low T3 and T4 without the big thyroid-stimulating hormone spike you see in congenital hypothyroidism.

In babies born before 28 weeks, T3 and T4 often only reach term-like peaks two to three weeks later. Some of that normalizes, but not all. In one series, nearly one-fifth of infants born before 32 weeks ended up on levothyroxine, and maternal hypertension heightened that risk.

A Swedish cohort followed into young adulthood found a 1.60-fold higher rate of medically treated hypothyroidism after extreme prematurity. Strikingly, about half of those treated had normal newborn screens, a reminder that a single test in the nursery can miss a moving target.

The pancreas tells a parallel story. Beta cells, which make insulin, multiply mostly in the third trimester. Cut that short, and both insulin levels and later diabetes risk shift.

A meta-analysis pooling about 2.2 million people estimated that preterm birth raises type 1 diabetes odds by about 20 percent and type 2 by roughly 51 percent. A massive Swedish cohort reported similar findings across the life course, with the type 2 signal especially strong in adult women. The type 1 pattern is nuanced—late-preterm and early-term births see a 10 percent to 20 percent higher risk, whereas the very earliest births sometimes showed lower risk—underscoring that biology doesn't always move in a straight line.

Cancer and immunity round out the edges. Several studies point to elevated risks for hepatoblastoma and acute myeloid leukemia in children born preterm, though estimates vary by cancer type and region. Findings on allergies are inconsistent.

Genetics and epigenetics are part of the backdrop—genome-wide studies have flagged variants tied to gestational timing, and DNA methylation patterns can carry signatures of early birth for years. There's an intergenerational echo too: women born preterm are more likely to deliver preterm themselves. Whether those signals directly drive later multisystem disease is still an open question.

All of this lands in real lives. Educational supports are needed more often, not just for motor challenges but for attention, working memory, language, and sensory integration. German adolescents born extremely preterm reported more psychological difficulties and lower health-related quality of life, which shows up in peer relationships and classroom behavior.

Health service use tells the same story: more specialized outpatient care, more school-based supports, and more touchpoints with systems that often aren't designed to talk to each other.

And as babies become adults, participation and independence are on the line. Norwegian longitudinal data linked extreme prematurity with higher reliance on disability pensions in adulthood. Large Swedish studies documented higher rates of antihypertensive use, ischemic heart disease, heart failure, and chronic kidney disease across the lifespan after preterm birth.

These aren't isolated events; they're the downstream of early cardiometabolic and neurodevelopmental trajectories. The practical takeaway from Gette and colleagues is straightforward: build structured transitions from pediatric to adult care, and keep surveillance going for cardiovascular, metabolic, renal, and mental health comorbidities.

So where does that leave us? First, with pattern and nuance. Risks rise as gestational age falls, but there's real heterogeneity.

Many preterm survivors thrive; some need targeted, time-sensitive help. Second, with agency. Proactive monitoring works best when it's holistic—hearing and vision screens, school supports, neurodevelopmental check-ins, and monitoring of blood pressure and kidney health, thyroid and glucose over time. Families ask for continuity; systems should make it the default.

Finally, with a research agenda that's refreshingly concrete. We need larger, harmonized, longitudinal cohorts that follow people from the neonatal unit into midlife, across organs and outcomes. We need to tighten the links between early biological signals—like cytokines, lung imaging, kidney injury—and later disease.

Not because we don't know enough to act, but because precise timing and targeted interventions could shift arcs that begin before the first birthday and trace through a lifetime.