How Can Preterm Birth Affect a Child?

Preterm birth found to have large effect on various physical and social outcomes

/ Author:  / Reviewed by: Robert Carlson, M.D Beth Bolt, RPh

(RxWiki News) Babies born very early during pregnancy can be at risk of having developmental issues. But how exactly are preterm offspring's lives affected?

A recent study was conducted to see if the increased risks of mortality (death rate) and morbidity (disease rate) associated with preterm birth were due to outside environmental factors (poverty, family life, genetic factors), or the biological effects of preterm birth.

The researchers found that preterm birth was associated with early mortality, psychiatric, academic, and social problems. Preterm birth was also associated with a decreased likelihood of criminal and substance abuse problems. 

The researchers concluded that there is a need for comprehensive service programs aimed at helping families dealing with preterm birth. The researchers hope to spread awareness on the risks surrounding preterm birth.

"Keep all prenatal appointments."

This study was conducted through the Department of Psychological and Brain Sciences at Indiana University-Bloomington in Bloomington, Indiana and the Department of Medical Epidemiology and Biostatistics at the Karolinska Institutet in Stockholm, Sweden. The lead author was Brian M. D'Onofrio, PhD, from Indiana University-Bloomington.

The researchers used the Swedish Medical Birth Registry to select a group of 3,300,708 people born in Sweden between January 1, 1973, and December 31, 2008. All participants were single births, with gestational periods (time spent in womb) between 23 weeks and 42 weeks, 6 days.

Typical gestation for this study was from 38 to 42 weeks 6 days.

The researchers split the study population into five different groups by length of gestation: 23 weeks to 27 weeks 6 days; 28 weeks to 30 weeks 6 days; 31 weeks to 33 weeks 6 days; 34 weeks to 36 weeks 6 days; and 37 weeks to 42 weeks 6 days.

The researchers then used multiple other national registries to categorize the participants by mortality, psychiatric morbidity, academic problems, and social adversity.

Mortality was split up into two groups: the people who had died in infancy before one year of age, and those who died after the age of one. Morbidity was broken up into six psychiatric areas: psychotic or bipolar disorder, autism, ADHD, substance abuse, suicidal actions, and criminality.

The researchers then categorized the participants into three areas of academic issues: failing grades, education of less than 10 years, and completion of post-secondary education. Social adversity was also examined, with the researchers using three areas: if/when someone became a parent, was in a marriage or civil union, and what age they began receiving social welfare.

The researchers found that there was a strong association between gestational period and infant mortality. The participants born after 23 to 27 weeks were found to be almost 300 times more likely to die during infancy compared to offspring who were born after 38 weeks gestation.

Those born after 28 to 30 weeks were found to be 70 times more likely to suffer infant mortality, participants born after 31 to 33 weeks were 25 times more likely, and those born at 34 to 36 weeks were seven times more likely to die during infancy.

Extreme early gestation was considered 23 to 27 weeks, and this group was found to be at three times greater risk of dying after the age of one. The researchers found that this group was also at three times greater risk of developing psychotic or bipolar disorder, at three times greater risk for autism, and at two times greater risk for developing ADHD.

The researchers found that autism and ADHD were not factors shared by siblings and were independent of any other variables so these conditions were directly related to preterm birth. Psychotic and bipolar disorder were found to be the result of environmental factors.

The participants in the 23 to 27 week group were found to have about a 70 percent higher risk of attempting suicide at least once in their life. The researchers determined that this was due to environmental factors.

Early gestation was also associated with a 50 percent decreased risk for substance abuse, and 30 percent decreased risk of committing a crime. These issues were found to be directly related to preterm birth.

In terms of academics, the researchers found that the 23 to 27 week group was two times more at risk for having failing grades, 70 percent more at risk for completing less than ten years of school, and there was a decrease of 50 percent in the likelihood of completing three or more years of post secondary education.

The researchers found that failing grades were directly related to preterm birth, whereas the level of education completed was the result of environmental factors.

The 23 to 27 week group was associated with a 30 percent decrease in the likelihood of ever being biological parents, and 80 percent decrease in the likelihood of getting married or being in a registered partnership. The researchers found that these trends were directly related to preterm birth.

In contrast, the researchers found that early gestation was associated with a 30 percent increased likelihood of receiving social welfare benefits. This was found to be related to environmental factors.

The researchers explained that the conditions and events that were found to be associated with preterm birth directly are associated with the physical, biological, and intellectual immaturity of human development associated with preterm birth. The issues that were found to be the result of environmental factors are related to preterm birth and are thus secondary results.

The authors noted a few limitations.

First, Sweden has universal health care coverage so the researchers believe that the study needs to be done in a country without that type of healthcare system to see if these results are generally applicable to other populations. Second, the sibling comparison method could not account for any individual offspring-specific genetic issues. Third, the researchers believe that they could have over- or underestimated the significance of some associations.

This study was published online ahead-of-print on September 25 in JAMA Psychiatry.

The National Institute of Child Health and Human Development, the National Institute of Mental Health, the Swedish Research Council, and the Swedish Prison and Probation Services provided funding.

Review Date: 
September 27, 2013
Last Updated:
September 30, 2013