Attachment and mother-infant interactions in dyads with infants born full-term, moderate-to-late preterm, and very-to-extreme preterm.

Background: The impact of prematurity status on attachment quality remains indeterminate. Some studies found no differences between infants born preterm (PT) and infants born full-term (FT), while other investigations present opposite results.

Aims: We aim to contribute to this body of research by studying mother-infant interactive behaviors and quality of attachment in 3 independent samples: Full-Term (FT), Moderate-to-Late Preterm (MLPT) and Very-to-Extreme Preterm (VEPT).

Study Design: This is a longitudinal laboratory study conducted from 3 to 12 months of age (corrected-age in the case of infants born PT).

Subjects: The participants are 213 Portuguese infants (FT = 105; MLPT = 52; VEPT = 56) and their mothers.

Outcome Measures: Mother-infant interactive behavior was observed in free-play at 3 and 9 months (corrected-age). Infant attachment was observed in Strange Situation at 12 months.

Results: Secure attachment is more prevalent in infants born FT, and ambivalent attachment is more prevalent in infants born VEPT. Infants with a secure attachment have higher gestational age and weight at birth. Infant and maternal interactive behavior quality is associated with attachment patterns and varies according to infant prematurity status. Last, the results indicate changes in maternal sensitivity and infant difficult behavior from 3 to 9 months of infant's age.

Conclusions: Our findings indicate that prematurity status impacts attachment quality. Changes in maternal and infant behavior from 3 to 9 months suggest a period of rapid non-linear development, supporting a transactional multilayered approach to the study of mother-infant relationship.