BACKGROUND: Depression ranks as the foremost mental health concern among childbearing women. Within low- and middle-income countries (LMICs), between 20 and 25% of women encounter depression during pregnancy or soon after delivery. This condition impacts not only the mothers but also their offspring. Offspring of women suffering from postnatal depression (PND) exhibit suboptimal cognitive development and increased emotional and behavioural issues throughout their growth. This scenario becomes more pronounced in LMICs, where numerous adversities further jeopardise children's developmental progress. Despite antenatal services providing a pivotal platform to address women's mental health needs, PND treatment remains inaccessible in many LMICs. The World Health Organization advocates interpersonal psychotherapy (IPT) for treating depression. While research from high-income countries has established the efficacy of IPT and group-IPT (g-IPT) for PND, its effectiveness within the LMIC context and its potential benefits for child development remain uncharted. This study seeks to gauge the potency of g-IPT for women with PND in two LMICs.

METHODS: This multi-site randomised controlled trial is a continuation of two preceding phases-conceptual mapping and a feasibility study executed in Lebanon and Kenya. Insights gleaned from these phases underpin this comprehensive RCT, which contrasts the efficacy and cost-effectiveness of high-quality standard care (HQ-SC) augmented with g-IPT against HQ-SC in isolation. The trial, characterised as an individually randomised superiority assessment, targets women with postnatal depression in Beirut, Lebanon, and Nairobi, Kenya. It aims to determine if culturally tailored g-IPT, administered within community settings in both countries, outperforms HQ-SC in influencing child developmental outcomes, maternal depression, and the quality of the mother-child bond.

DISCUSSION: The SUMMIT trial, designed with pragmatism, possesses the magnitude to evaluate g-IPT within two LMIC frameworks. It seeks to enlighten policymakers, service commissioners, professionals, and users about g-IPT's potential to alleviate maternal PND and bolster child developmental outcomes in LMICs. Additionally, the trial will generate valuable data on the clinical and economic merits of high-quality standard care.

TRIAL REGISTRATION: ISRCTN, ISRCTN15154316. Registered on 27 September 2023, https://doi.org/10.1186/ISRCTN15154316.