AIM: We review methods and outcomes of a novel parenting intervention, Family Nurture Intervention (FNI), that promotes early mother-infant autonomic co-regulation and emotional connection in the neonatal intensive care unit (NICU). METHODS: FNI involves individualised mother-infant calming sessions combined with maternal emotional expression. Two parallel group randomised controlled trials have evaluated FNI. The first, recruited 150 preterm newborns (26-34 weeks GA) and their mothers, randomised into two groups: FNI (n = 78) and Standard Care (SC) only (n = 72). Dyadic, infant and maternal outcomes were assessed at discharge, 18-months and 4-5 years corrected age. The second,recruited 135 infants from two level 4 NICUs (FNI n = 66, SC n = 69) with similar outcomes assessed at discharge/term equivalent. RESULTS: Relative to SC, FNI infants showed improved development and relational health through 5 years. At term age, FNI infants had better autonomic regulation and more mature brain activity and cortical connectivity on EEG. FNI mothers also reported fewer anxiety and depression symptoms post-discharge. At 18-month, FNI infants obtained higher cognitive and language scores, and lower attention and social behaviour scores than SC infants. CONCLUSIONS: FNI improves the early life development and relational health of high-risk preterm infants. Further research is important to assess its efficacy in other high-risk populations and contexts.