Strengths and Limitations
ADVERSE EVENTS, RECRUITMENT
Strengths of the study included multicountry representation from a diversity of clinical settings, good per protocol intervention completion rates (83% NICU MT, 60% postdischarge MT), high study retention rates (95%), and use of a wide array of psychometrically strong measurement tools. Lack of adverse events or longer-term detrimental outcomes linked to the intervention and high intervention completion suggest that the treatment was safe, consistent with tenets of individualized developmental care,This study had several limitations, including a potential lack of sensitivity in the PBQ to detect improvements for mothers who report good mother-infant bonding at baseline, and the possibility of a floor effect where low scores on baseline PBQ precluded the ability to detect changes over time. In addition, we relied on parental self-report, which may have led to social desirability bias, particularly with the PBQ. We cannot exclude the possibility of contamination effects in the NICU phase, as 6 of our 8 participating NICUs had at least some number of shared rooms. We encouraged fathers to engage in MT sessions as we hoped doing so would contribute to infant outcomes and paternal well-being; however, fathers participated in only 25% of MT sessions in both phases. Although all music therapists were trained in neonatal care and in the study protocol, they had differing lengths of NICU experience. The onset of the COVID-19 pandemic in March 2020 affected our final recruitment and led to a small number of postdischarge MT sessions being held online (eTables 1 and 2 in Our results suggest that risk of problematic mother-infant bonding may vary across cultural contexts and may not be an appropriate target of intervention for all preterm mothers.