Differential Susceptibility Effects of Maternal Sensitivity in Childhood on Small for Gestational Age (SGA) Adults' Wealth

Small for gestational age (SGA) birth has been shown to have adverse consequences on health and is considered as a developmental vulnerability. However, in-utero protection of the brain may not increase vulnerability but rather result in higher individual susceptibility to environmental experiences. The aim was to test if individuals born SGA are more susceptible to both negative and positive environmental experiences assessed by sensitive parenting in childhood compared to those born appropriate for gestational age (AGA). The target outcome was economic success in young adulthood. 438 participants (SGA n = 109, AGA n = 329) were studied as part of the Bavarian Longitudinal Study, a prospective, geographically defined investigation of neonatal at-risk children in South Germany. Maternal sensitivity was observed during a standardized mother-child interaction task, and IQ was defined as a K-ABC MPC Score at age 6 years. At age 26, participants’ wealth was assessed as a comprehensive composite score. Comparative analysis confirmed that individuals born SGA were more susceptible to the positive effects of sensitive parenting after controlling for gestational age and IQ at age 6 years. This means, if maternal sensitivity was lower than average, SGA adults did worse than AGA adults, but with high sensitivity in childhood they were significantly more successful than their AGA peers at 26 years of age. It appears that adverse uterine conditions resulting in SGA birth may alter susceptibility to environmental experiences in a for-better-or-for-worse way. Increasing parental sensitivity is a likely avenue to improve life outcomes for SGA individuals.