What Are the Risks of Disability After Premature Birth?

Possible Links to ADHD, Asthma, Autism, and Cerebral Palsy

When you deliver your baby prematurely, it doesn’t take long for the worries to start. Between the doom and gloom statistics that doctors share, the scary questions your friends and family ask, and the natural concern of a parent, it can be hard to feel secure at all about your baby’s future.

Thinking about unpleasant long-term outcomes for sweet, innocent babies can be heart-wrenching. But many parents yearn for the truth, even when it might be less-than-ideal. For many, understanding the risks and knowing what to look out for is empowering.

The hard truth is that babies born prematurely are more likely to develop complications in the short and long term.

Let's take a look at four major disorders—autism, ADHD, asthma, cerebral palsy—and share what the latest scientific research shows on how these conditions relate to premature birth.

And then we’ll look at what parents and care providers can do to learn more and know what to look for.

1
Before We Get Started

Premature baby
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If your baby is newly born and in the NICU, it might be comforting to look at the statistics here, or it simply might add to your already high stress level.

If it’s likely to just stress you out, you might consider bookmarking this page and returning to it when you’re in a calmer state. There’s no need to add unnecessary stress to your life right now!  

But if you'd like to know what recent research shows, you're at the right place.

And let's be clear—statistics are just that—numbers. They are not your child, they are not guarantees. Many parents have looked back at all of the worry they carried and wished that they hadn't. Worrying, as they say, is like a rocking chair—it gives you something to do, but it gets you nowhere. 

Also, remember to look at the whole picture. When one study shows that a preemie is three times more likely to have an issue than a non-preemie, that may seem alarming and scary. But in that case, if only 1 percent of all full-term babies have a particular disorder, that means that only 3 percent of preemies would have the disorder, which of course means 97 percent of preemies don’t have it. 

As a parent or care provider of preemies, the more you know what to look out for, the better you can care for your child. But try not to let worry about possible outcomes keep you from adoring and nurturing your baby with every ounce of your love!

2
Chances of ADHD Affecting Preemies

ADHD is a chronic condition that affects millions of children, and it often continues into adulthood. ADHD includes a combination of persistent problems, such as hyperactivity, difficulty sustaining attention, and impulsive behavior.

So, how many children are affected, and how many of them are preemies?

Let’s start off by putting ADHD in perspective.

In the United States, according to the Centers for Disease Control and Prevention, it is estimated that 11 percent of U.S. school age children had received an ADHD diagnosis by 2011. That means 89 percent of children in the U.S. do not have an ADHD diagnosis. 

A study in 2003 indicates that the rates of ADHD are very likely similar globally.  

Most research does find a link between premature birth and ADHD.

And generally, it is what you might expect; the risk of ADHD increases as gestational age at the time of birth decreases. So, the risk is higher the earlier a baby is born. 

Even some nearly full-term infants—those born between 34 to 36 weeks—did show increased evidence of ADHD, depending on the reason for preterm birth. Other research shows no link between late preterm birth and ADHD or learning disability.  

But how can they be sure this ADHD is really related to prematurity and not other factors, such as genetics or socioeconomic factors? One way is to compare siblings. In families that share genetic commonalities and live in the same social and economic environments, ADHD is still higher for the siblings who were born prematurely. 

What is also interesting, however, is that ADHD is also linked to weight at birth, with an increased risk for ADHD for small-for-gestational-age AND large-for-gestational-age. 

So, each week a baby is born early increases the chances of ADHD. And variations in fetal growth—either underweight or overweight—also increase likelihood of ADHD. 

So, does this mean prematurity causes ADHD? That is yet to be determined. Most research shows a link between the two, but cannot say prematurity causes ADHD. The factors that contributed to the premature birth may, in fact, be the cause, or there may be other causes. But the two are definitely linked, according to the research.

If you'd like to learn more, check out this information on ADHD evaluation and diagnosis.

3
Chances of Asthma Affecting Preemies

Asthma is a respiratory condition marked by spasms in the bronchi of the lungs, causing difficulty in breathing. Often, it is triggered by an allergic reaction or other forms of hypersensitivity.

Premature birth does seem to increase the risk of a child having asthma. And again, as would be expected, the risk increases as the gestational age at birth decreases.  

2014 review of research showed that 13.7 percent of preterm babies developed asthma/wheezing disorders during childhood, compared to only 8.3 percent of babies born at term. 

But while the link is clear, and asthma does seem more prevalent in former preemies, another way to look at the numbers shows that the risk is fairly low—approximately 3 percent of the children who have wheezing disorders were born prematurely, which means 97 percent of children with wheezing disorders were not born prematurely. 

A 2011 study confirmed that even nearly full term birth, 34 to 38 weeks, can have increased risk relative to babies born at full term.  

If you would like to better understand this condition, you can learn more about asthma in children.

4
Chances of Autism Affecting Preemies

Autism is defined as a mental condition, present from early childhood, characterized by difficulty in communicating and forming relationships with other people and in using language and abstract concepts.

An estimated 1 out of 42 boys and 1 in 189 girls are diagnosed with autism in the United States, as of 2016.

Recent research indicates that roughly 2 to 4 percent of children with Autism Spectrum Disorder were born prematurely.

However, 7 to 8 percent of children with Autism Spectrum Disorder were born by cesarian section, so the link to prematurity is weaker than a link to mothers who delivered by c-section.  

This does not mean that prematurity causes autism, nor c-section birth, but rather that they are linked. It’s possible that whatever caused the mother to deliver preterm, or to deliver by c-section, is also related to autism.  

Autism is generally linked to genetic factors, but it does seem that environmental factors such as preterm birth, low birth weight, delivery by cesarian section, and others can contribute to autism.  

One recent study in 2015 did find evidence of changes in the brain structure in babies born very prematurely—less than 27 weeks gestation—which corresponded to higher risk of autism.  

And another large study found that autism is approximately 3 times more prevalent in these same micro preemies, born at under 27 weeks.

Another study attempted to compare siblings, in order to rule out factors such as genetics and socioeconomic factors, and they still found a higher correlation between early gestational age at birth and autism.  

If you'd like to learn more about this, you can find many helpful articles on autism.

5
Chances of Cerebral Palsy Affecting Preemies

CP stands for Cerebral Palsy, and it is considered a neurological disorder caused by a non-progressive brain injury or malformation which occurs while the child’s brain is under development.

CP affects a child's ability to move or walk, but the problem isn't in the child's muscles or nerves. Instead, the child's brain itself has damage which affects his ability to control his muscles.

How many preemies are affected by CP? Let’s take a look at one a 2014 study from Norway of nearly 2 million children over a 34 year time period.

Of babies who were born at the following gestational ages, this is the percentage who were diagnosed with cerebral palsy:

  • less than 28 weeks = 8.5% 
  • 28-30 weeks = 5.6% 
  • 31-33 weeks = 2% 
  • 34-36 weeks = 0.4% 
  • 37+ weeks = 0.1 

Another large study in Developmental Medicine and Child Neurology, published in 2013, pooled the results of 49 different studies on prematurity and cerebral palsy.

In this study, out of 1000 babies born at the following gestational ages, this is the number of them who were diagnosed with cerebral palsy:

  • less than 28 weeks = 82.3 out of 1,000
  • 28-31 weeks = 43.2 out of 1,000
  • 32-36 weeks = 6.8 out of 1,000
  • 37+ weeks = 1.4 out of 1,000

So, if your little one was born less than 28 weeks, you may be feeling worried. But please keep in mind, with these statistics, it means your baby has a 91.5 percent chance of not having cerebral palsy.

Would you like to learn more about cerebral palsy? You'll find a fantastic selection of information on cerebral palsy in children here.

Sources:

Minna Sucksdorff, et al. “Preterm Birth and Poor Fetal Growth as Risk Factors of Attention-Deficit/Hyperactivity Disorder” Pediatrics, August 2015.

Stephen V. Faraone, et al. “The worldwide prevalence of ADHD: is it an American condition?” World Psychiatry. 2003 Jun; 2(2): 104–113.

Karolina Lindström, et al. “Preterm Birth and Attention-Deficit/Hyperactivity Disorder in Schoolchildren.” PEDIATRICS Vol. 127 No. 5 May 01, 2011

Malinda N. Harris, et al. “ADHD and Learning Disabilities in Former Late Preterm Infants: A Population-Based Birth Cohort.” Pediatrics. 2013 Sep; 132(3): e630–e636.

Jasper V. Been, et al. “Preterm Birth and Childhood Wheezing Disorders: A Systematic Review and Meta-Analysis.” PLOS, January 28, 2014

Huan He, et al. “Preterm Birth with Childhood Asthma: The Role of Degree of Prematurity and Asthma Definitions.” American Journal of Respiratory and Critical Care Medicine, Vol. 192, No.4 (2015), pp. 520-523.

Laura A. Schieve, PhD, et al. “Population attributable fractions for three perinatal risk factors for autism spectrum disorders, 2002 and 2008 autism and developmental disabilities monitoring network.” Ann Epidemiol. 2014 Apr; 24(4): 260–266.

Maryam Oskoui, et al. “An update on the prevalence of cerebral palsy: a systematic review and meta-analysis” Developmental Medicine & Child Neurology
Volume 55, Issue 6, pages 509–519, June 2013

Håvard Trønnes, et al. “Risk of cerebral palsy in relation to pregnancy disorders and preterm birth: a national cohort study.” Developmental Medicine & Child Neurology Volume 56, Issue 8, pages 779–785, August 2014.

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