People who are born very prematurely or with a very low birth weight are at an increased risk of being introverted, neurotic and averse to taking risks as adults, according to the findings of a new study.

Pensive man sits with hand on window.Share on Pinterest
The study suggests that, for some individuals, the physiological circumstances of birth could explain career and relationship difficulties in adulthood.

The study, published in the Archives of Disease in Childhood (Fetal & Neonatal Edition), provides a personality profile for this group that, the authors suggest, may help to partly explain the social difficulties these individuals experience in relationships and their careers.

“Personality characteristics are very important because they help people to develop into adult roles and form and maintain social relationships,” states lead author Prof. Dieter Wolke of the University of Warwick, UK.

“Very premature and very low-birth-weight adults who have a socially withdrawn personality might experience difficulty dealing with social relationships with their peers, friends and partners.”

Previous research has revealed that individuals born after less than 32 weeks gestation and/or with a very low birth weight are at an increased risk of developing autistic spectrum behaviors. It has also been consistently shown that adults who were born very prematurely and/or severely underweight are less likely to exhibit risk-taking behaviors than peers born full term.

However, experts have been uncertain as to whether being born at less than 32 weeks and/or with a birth weight of less than 1.5 kgs has a bearing on other adult personality traits.

To investigate, Prof. Wolke and colleagues compared the personality traits of 200 26-year-olds who were born either after less than 32 weeks and/or with a birth weight of less than 1.5 kgs to 197 other young people born in the same obstetric units at full term and with weights in the normal range.

The researchers aimed to find out whether extreme prematurity and low birth weight led to a specific personality profile or whether low IQ – also associated with premature birth – could explain any personality differences.

Five dimensions of personality traits were measured and assessed: agreeableness, conscientiousness, introversion, neuroticism and openness to new experiences.

Participants who were born very prematurely and/or had a very low birth weight scored significantly higher than the control participants in three of the five categories: agreeableness, introversion and neuroticism. These significant differences remained even after adjusting scores for the influence of other potential risk factors, such as low intelligence.

In addition, those who were born very prematurely or with very low birth weights also reported significantly higher levels of autism spectrum behaviors and lower levels of risk taking.

Following these findings, the researchers were able to construct a personality profile for this group, comprised of a cluster of traits that describe a “socially withdrawn personality”: introverted, averse to risk taking, neurotic and exhibiting autism spectrum behaviors.

Prof. Wolke believes that this personality profile may be attributable to brain development and a combination of changes in how the brain develops as a result of premature birth and “prenatal and neonatal insult.”

Being born very prematurely or with a very low birth weight may also lead to parents being overprotective toward their children, potentially influencing the development of particular personality traits.

“Defining a general personality profile is important because this higher order personality factor may help to partly explain the social difficulties these individuals experience in adult roles, such as in peer and partner relationships and career,” Prof. Wolke states.

“If identified early, parents could be provided with techniques to foster their child’s social skills to help compensate for socially withdrawn personality characteristics,” he adds.

Evidence suggests that adults who were born very prematurely and/or with a very low birth weight are less likely to gain degrees, attain high-earning employment, build and maintain relationships or have children of their own. With early intervention, perhaps these outcomes could change.

Earlier this year, Medical News Today reported on a study that found premature birth reduces connectivity in brain regions linked to cognitive functioning.