The fetal programming hypothesis suggests that an adverse in utero environment, reflected in small body size at birth, has life-long effects on different physiological systems that may affect both health and behavior. We explored whether fetal growth was associated with biologically based temperamental outcomes (negative affectivity scales, the CBQ) among 5(1/2)-year-old children (n = 416) born healthy at term (gestational weeks 37-42). In line with the hypotheses, small body size at birth (thinness measured by ponderal index, kg/m(3)) was related to increased negative affectivity and its subscales: anger-, discomfort-, and sadness-proneness in childhood. Longer length at birth was predictive of higher levels of child anger- and sadness-proneness. Length of gestation moderated the associations of weight and length at birth with negative affectivity. The results suggest that the biological basis of temperament may be subjected to antenatal environmental influences, and that the mechanisms, proposed to be related to fetal glucocorticoid environment, may operate even within the normal range of term birth.
(c) 2006 Wiley Periodicals, Inc.