This study assessed participant, facilitator, and program-level characteristics associated with intervention dosage among women receiving an evidence-based perinatal depression preventive intervention, Mothers and Babies (MB). We also explored how intervention dosage affected the use and maintenance of core skills taught in the six-session group-based intervention. We conducted a secondary analysis of data from a cluster-randomized controlled trial in which 679 women enrolled in home visiting (HV) programs received MB prenatally. High dose of intervention was defined as attendance at > 50% of MB sessions, while MB skill utilization was measured by asking participants to indicate at 12 and 24 weeks postpartum the extent to which they used 12 core MB skills taught during the intervention. Age and racial concordance between participant and facilitator were significantly associated with intervention dosage. Those receiving higher intervention dosage tended to be older (27.25 ± 5.96 vs. 24.99 ± 5.60, p < 0.01, OR = 1.068 [1.038-1.098]), and received MB from a facilitator with a self-identified race similar to their own (58% vs. 48%, p = 0.04, OR = 1.485 [1.014-2.176]). Primary language of participants was marginally associated with dosage. Participants receiving a higher dose of intervention tended to exhibit greater MB skill utilization, on average at 24 weeks postpartum. These results can be used to identify strategies to promote intervention engagement. They further suggest that greater intervention dosage leads to increased use of core intervention skills that can promote improvements in participants' behaviors and thoughts.
Keywords: Fidelity; Home visiting; Implementation science; Intervention; Postpartum depression.
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