This article explores how childbirth shaped the information networks that London Missionary Society missionaries helped develop between Britain and the South Pacific from the late eighteenth century. As Evangelical missionaries experienced challenging births in the South Pacific, they sought new forms of cultural knowledge, which they recorded in their reports to the society. Part of these knowledge networks included books on medicine and midwifery that the missionaries ordered from Britain. From the 1820s, moreover, some missionaries came to collate early forms of ethnographical and anthropological research on Pacific peoples, which examined indigenous ways of birth and postnatal care.