BackgroundAccelerating improvements in maternal and newborn healthcare is a major public health priority in Kenya. While utilization of formal healthcare has increased, many pregnant and postpartum women do not receive the recommended number of maternal care visits. Even when they do, visits are often short with many providers not offering important elements of evaluation and counseling, leaving gaps in women’s knowledge and preparedness. Digital health tools have been proposed as a complement to care that is provided by maternity care facilities, with the potential to empower patients to receive the right care at the right place and time. However, there is limited evidence of the impact of digital health tools at scale on patients’ knowledge, preparedness, and the content of care they receive. We evaluated a digital health platform (PROMPTS) composed of informational messages, appointment reminders, and a two-way clinical helpdesk that has been implemented at scale in Kenya on six domains across the pregnancy-postpartum care continuum.Methods and FindingsWe conducted an unmasked, 1:1 parallel arm cluster randomized controlled trial in 40 health facilities (clusters) across eight counties in Kenya. 6,139 pregnant individuals were consented at baseline and followed through pregnancy and postpartum.Individuals recruited from treatment facilities were invited to enroll in the PROMPTS platform, with roughly 85% reporting take-up. Our outcomes were derived from phone surveys conducted with participants at 36-42 weeks of gestation and 7-8 weeks post-childbirth. Among eligible participants, 3,399/3,678 women completed antenatal follow-up, and 5,509/6,128 women completed postpartum follow-up, with response rates of 92% and 90%, respectively. Outcomes were organized into six domains: knowledge, preparedness, routine care seeking, danger sign care seeking, newborn care, and postpartum care content. We generated standardized summary indices to account for multiple hypothesis testing but also analyzed individual index components.Intention-to-treat analyses were conducted for all outcomes at the individual level, with standard errors clustered by facility. Participants recruited from treatment facilities had a 0.08 standard deviation (SD) (95% CI: 0.03, 0.12) higher knowledge index, a 0.08 SD (95% CI: 0.02, 0.13) higher preparedness index, a 0.10 SD (95% CI: 0.05, 0.16) higher routine care seeking index, a 0.09 SD (95% CI: 0.07, 0.12) higher newborn care index, and a 0.06 SD (95% CI: 0.01, 0.12) higher postpartum care content index than those recruited from control facilities. No significant effect on the danger sign care seeking index was found (95% CI: -0.01, 0.08).A limitation of our study was that outcomes were self-reported, and the study was not powered to detect effects on health outcomes.ConclusionsDigital health tools indicate promise in filling gaps in pregnant and postpartum women’s health care, amidst systems that fail to deliver a minimally adequate standard of care. Through providing patients with critical information and empowering them to seek recommended care, such tools can ensure that individuals are prepared for a safe childbirth and receive access to comprehensive, high quality postpartum care. Future work is needed to ascertain the impact of at-scale digital platforms like PROMPTS on health outcomes.Trial RegistrationClinicalTrials.gov ID:NCT05110521; AEA RCT Registry ID:R-0008449