The assessment of the quality of infants’ spontaneous movements is a diagnostic tool for the young nervous system. We examined whether it relates to the quality of the interactions between infants born preterm and their mothers. Thirty‐nine healthy infants born preterm (Mage in weeks = 14.59, SD = 2.21; 38.46% female) and their mothers participated in the study. Infants’ quality of spontaneous movements was assessed using the General Movement Assessment according to Prechtl (Prechtl, Early Human Development 1990, 23, 151). A new measurement was employed to evaluate the following aspects of the mother–infant interaction: maternal sensitivity in the motor modality (i.e., when touching, picking up, holding, and putting down the infant), maternal sensitivity in the modalities of vocalization and eye contact, and infants’ positive engagement. Several aspects of infants’ quality of movements were associated with maternal sensitivity in the motor modality and infants’ positive engagement, but not with maternal sensitivity in the modalities of vocalization and eye contact. These findings suggest that the quality of infants’ spontaneous movements may explain some of the variability in the interactions between infants born preterm and their mothers. The results also highlight the importance of differentiating between the modalities of mothers’ behavior when assessing their sensitivity. Implications for research and practice with families of preterm infants are discussed.

Preterm-born infants and their mothers are at higher risk of showing less attuned interactions. We sought to identify characteristics of preterm-born infants associated with the attunement of mother-infant interactions at the corrected ages of 3-4 months, looking specifically at motor behaviors. We focused on infants' spontaneous movements, achievement of motor milestones, and temperament, which at this young age is often manifested via movement. Sixty preterm-born infants (Mdn gestation age in weeks = 33, 57.38% male, corrected age Mdn = 14 weeks, interquartile range = 13-16) and their mothers participated. Independent observers rated mother-infant attunement, infants' spontaneous movements, and infants' achievement of motor milestones.Mothers reported infant temperament. We found infants' smooth and fluent movement character and continual fidgety movements were associated with better attunement in terms of higher maternal sensitivity and non-intrusiveness and higher infant responsiveness and involvement. Unexpectedly, infants' achievement of motor milestones was not significantly associated with mother-infant attunement, and maternal reports of infants' higher soothability were associated with lower | 413 LEV-ENACABetal.