Early maternal and paternal vocal interactions following preterm birth: the role of birth weight, parental role and affective and stress symptomatology.

Preterm birth can be a profoundly stressful event for parents, complicating their transition to parenthood and the assumption of parental roles. Concerns regarding infant’s health and future outcomes as well as the emotional strain of early separation from the hospitalized newborn can affect parental stress and affective symptoms, negatively influencing parent-infant relationships and subsequent development. A critical element of early interactions is Infant-Directed Speech (IDS), a linguistic register characterized by unique linguistic and paralinguistic features that influence and sustain infants' cognitive and emotional growth. Given its affective nature, IDS is particularly responsive to fluctuations in parents’ emotional states. This PhD thesis includes a collection of four empirical studies that examine parental IDS directed toward full-term (FT) and preterm (PT) infants during the first year postpartum. The research focuses on factors influencing early interactions, including parental postnatal symptoms and the severity of prematurity, distinguishing between extremely low birth weight (ELBW) and very low birth weight (VLBW) infants. The first three chapters present a theoretical framework on premature birth and IDS. Chapter one details preterm birth risk factors and intervention strategies. Chapter two addresses parental adaptation challenges and mental health risks, while chapter three examines IDS characteristics and the influence of parental and infant risk factors on interaction patterns. The four empirical studies reveal significant findings regarding IDS in preterm contexts, demonstrating that lower birth weight and higher maternal depression may be associated with diminished affective salience and less engaging interaction styles. Additionally, the research highlights differences and similarities in IDS characteristics between mothers and fathers, emphasizing the importance of paternal involvement in fostering positive parent-infant relationships. This research offers some insights into how preterm birth and parental emotional well-being could influence the quality of early vocal interactions, informing clinical interventions aimed at supporting positive communication with premature infants.