Olfactory communication in the first weeks of life: from chemical mechanisms to improving breastfeeding outcomes

Successfully latching onto the mother's breast is critical for infant survival, growth, and health, while also enhancing bonding and maternal wellbeing. However, breastfeeding difficulties mean that fewer than half of infants worldwide are exclusively breastfed for the WHO's recommended period. We propose that uniquely human difficulties with breastfeeding might be ameliorated by recognising, understanding, and facilitating the olfactory mechanisms that, in every other mammal, regulate maternal-infant relationships in the first weeks of life. We therefore aim to describe the chemical mechanisms underpinning maternal-infant odour communication and understand the behavioural and physiological responses they induce. These aims require a novel interdisciplinary approach to measure real-time changes in odour chemistry across breastfeeding cycles. Having isolated functional compounds, we aim to experimentally confirm in bioassays that these simplified synthetic ‘odours’ are required and sufficient to stimulate the same behavioural and physiological responses as the intact odours. We will also use systematic reviews and interviews, surveys, and focus groups with relevant stakeholders to identify sociocultural barriers and facilitators of olfactory communication during breastfeeding in global perspective, and to design a digital behaviour change programme for practitioners. Our diverse approach should enable us to develop practical interventions and recommendations that can improve breastfeeding success worldwide.