Increased susceptibility to stress at a psychological assessment of stresstolerance is associated with impaired fetal growth

Background This study aims to investigate the relationship between birthwei ght and psychological function, as evaluated by the results of a psychologi cal conscript interview and assessment in young males, including an evaluat ion of stress susceptibility. Methods We performed a retrospective cohort study based on linked birth reg istry data and data from an assessment of psychological function during eva luation for military service. In all, 90 651 young males born 1973-1975, fo r whom birth record data were obtained from the Swedish Medical Birth Regis ter, were investigated in addition to psychological stress susceptibility d uring their conscript evaluation in 1991-1994. The assessment of psychologi cal functioning score, including the assessment of stress susceptibility, w as used as the dependent variable in a multiple regression analysis in comb ination with the following independent variables: birthweight, adult weight , head circumference at birth, month of birth, gestational age, maternal pa rity, and maternal age. Results The mean value was 5.1 (SD 1.9) on the psychological assessment sca le (range 1-9) of psychological level of functioning including evaluation o f stress susceptibility, and 5.3 (1.6) on the general psychological perform ance (leadership) profile. A positive association was seen between birthwei ght and better assessment results up to a level of about 4000 g birthweight , but above that an inverse association was seen. Positive correlations (P < 0.001) were seen between psychological assessment score results and birth weight (r = 0.07), gestational age (0.03), head circumference (0.05), and m aternal age (0.11), but inverse correlations with maternal parity (-0.11) a nd birth month of the offspring (-0.04). In multiple regression analyses, t he strongest independent correlations were seen between increasing assessme nt scores and maternal age and birthweight (positive), as well as with mate rnal parity and offspring adult weight (negative). Conclusion Young males at conscript testing show a better general psycholog ical functioning score derived from psychological assessment, including eva luation of stress susceptibility, with increasing birthweight up to 4200 g. Above that birthweight an inverse association is noticed. Impaired fetal g rowth is predictive of suboptimal psychological functioning and increased s tress susceptibility in males during early adult life.