Study of children born 1987–90 finds that those born preterm exhibit less risk-taking behaviour

Babies born preterm, meaning before week 37, exhibit less risk-taking behaviour as teens and young adults compared to those born full term, according to a population study conducted by the Finnish Institute for Health and Welfare (THL). 

The study showed that around one in three Finnish young people and young adults had at least one register entry for an event that can be interpreted as resulting from risk-taking behaviour. Such entries related to confirmed sexually -transmitted chlamydia infections, teenage pregnancies, crimes and fines, credit records and hospitalisations due to substance abuse. 

The study calculated that for every week of shortened pregnancy, the risk of a chlamydia infection decreased by 1.6%. Similarly, a reduction of one week in pregnancy length correlated with a decrease of 3.3% in the probability of teenage pregnancy. In addition, those born very preterm (less than 28 weeks of pregnancy) had a lower probability than those born full term of having entries in the register on crimes and fines. 

The study did not reveal any differences in the incidence of hospital treatments for substance abuse across those born during different pregnancy weeks.  Those born as very preterm (28–31 weeks of pregnancy), however, have a slightly higher risk of receiving a register record on payment default.

Factors that may underlie preterm birth, such as socio-economic status and age of the parents or maternal smoking during pregnancy, did not explain the generally lower level of risk-taking behaviour among those born preterm. Also of little impact were maternal pregnancy disorders, such as pregnancy diabetes and elevated blood pressure during pregnancy, risk-taking behaviour among the parents, and any chronic illnesses of the child. 

“According to the study, preterm birth is potentially an independent protective factor for risk-taking behaviour in adolescence and early adulthood,” says THL Professor Eero Kajantie, who is responsible for the study.

This was the first ever study examining the impact of preterm birth on the risk of risk-taking behaviour which included chlamydia infections, teenage pregnancies and credit records as possible indicators of risk-taking behaviour, and also took into account all levels of preterm birth from extreme preterm through to late preterm birth. 

Many reasons for the variation in behaviour

The study does not directly explain why preterm born individuals appear to exhibit less risk-taking behaviour. 

“Differences in behaviour among those born at different weeks of pregnancy may also be due to qualitative and quantitative differences in social interaction, different tempo of reaching adulthood, and differences in the parents’ upbringing style,” says researcher Suvi Alenius. 

“Some previous studies have used questionnaires to compare the characteristics and behaviour of adults that were born preterm with those that were born full term. These studies have found that in particular those born very preterm or with a very low birth weight have less externalising problem behaviour and, on the other hand, more challenges in forming social relationships. This could partly explain the findings of our register study,” Alenius adds. 

It was not possible, however, to examine the impact of these factors within a register study.

The research results emphasise the position of people born preterm as a special group among both those reaching adulthood and young adults. The results also draw attention to the many research questions that studies could answer in the future through methods such as qualitative interviews. In addition, the results leave it open to the reader to assess whether the findings should bring relief to those born preterm or their parents. 

“This research finding could be interpreted as the golden lining for the “cloud of prematurity”, but it could also be interpreted as describing many of the challenges connected with having been born preterm – challenges that have repercussions through to teenage years and early adulthood,” Alenius concludes.

The results are based on The Finnish 1987–90 Birth Cohort, and the research took into account, within certain limits, all those born in Finland between 1987 and 1990. The study covered a total of 191,705 young people and young adults as well as their parents. Of these young people and young adults, 8,492 had been born preterm. 

The study combined the Medical Birth Register, Register of Congenital Malformations, Care Register for Health Care, Register for Pregnancy Terminations and Sterilisation and National Infectious Diseases Register maintained by the Finnish Institute for Health and Welfare, with the register data of five other register holders. These other register holders included the Digital and Population Data Services Agency, Statistics Finland, the Social Insurance Institution of Finland (KELA), the Legal Register Centre and Suomen Asiakastieto Oy.

The study was published in The Journal of Pediatrics on 27 September 2022.

Source

Suvi Alenius, Eero Kajantie, Reijo Sund, Markku Nurhonen, Peija Haaramo, Pieta Näsänen-Gilmore, Marja Väärsmäki, Sakari Lemola, Katri Räikkönen, Daniel D. Schnitzlein, Dieter Wolke, Mika Gissler, Petteri Hovi. Risk-taking Behavior of Adolescents and Young Adults Born Preterm. The Journal of Pediatrics. In press. Published online first 27 September 2022. doi: 10.1016/j.peds.2022.09.032

Further information

Suvi Alenius
Researcher
Finnish Institute for Health and Welfare
[email protected]
tel. +358 29 524 6031

Petteri Hovi
Senior Researcher
THL
[email protected]
tel. +358 29 524 8941

Eero Kajantie
Research Manager
Finnish Institute for Health and Welfare
[email protected]
tel. +358 29 524 8610

The Finnish 1987–90 Birth Cohort  
Children born preterm are more likely to be placed outside the home. Press release 27 December 2019, THL. (in Finnish).