Evaluation of a complex intervention: the Latch On randomized controlled trial of multicomponent breastfeeding support for women with a raised body mass index

Background: Latch On's objective was to achieve improved breastfeeding rates in women with raised body mass indices using a multicomponent breastfeeding support intervention. Methods: A hybrid type 1 implementation-effectiveness trial with mixed-methods process and health economics analyses were conducted. Data collection included stakeholder questionnaires, interviews, focus groups, fidelity data, participant and health system costs. Results: The intervention was delivered with fidelity but the high breastfeeding rates at 3 months were not different between intervention and usual care. Participants receiving the minimum intervention dose were more likely to initiate breastfeeding (P = 0.045) and be breastfeeding at hospital discharge (P = 0.01) compared with participants below the threshold. Participant exit interview themes highlighted the importance of improving breastfeeding support to women, the effect of COVID-19 on the breastfeeding experience, and found that the intervention improved the experience of establishing breastfeeding. The intervention cost €157 per participant, with no other cost difference between groups. Process analysis found that follow-up breastfeeding services continued in half of sites after study completion. Conclusions: This low-cost intervention resulted in a more enjoyable breastfeeding experience for participants and changed practice in some study sites. The intervention dose received may impact effectiveness, but further research is needed to provide definitive evidence of clinical and cost effectiveness.