Health systems and healthcare delivery around the world have been greatly affected by the COVID-19 pandemic. In Kenya, the attainment of universal health coverage (UHC) has been hampered by the pandemic, particularly in the areas of reproductive, maternal, newborn, and child health (RMNCH). This paper examines the effect of COVID-19 on RMNCH in Kisumu, Isiolo, Machakos, and Nyeri counties in Kenya. The objective of the study was to determine if there was a significant change in service delivery under reproductive, maternal, newborn, and child health in hospitals under the Universal Health Coverage Program. The target population was the patients seeking RMNCH services in these hospitals. The study arrived at a sample of 78 respondents achieving a response rate of 84%. The study used a mixed-methods approach, comprising both quantitative and qualitative data collection methods. The quantitative data were collected through a retrospective analysis of RMNCH indicators from January 2019 to June 2021, while the qualitative data were collected through in-depth interviews with healthcare workers and community members. The key finding of the study was that there was a significant decrease in the quality of RMNCH services during the COVID-19 period compared to before the pandemic. This conclusion is based on the results of a Wilcoxon Signed Ranks Test, which produced a test statistic Z of -4.321 and an Asymp. Sig. (2-tailed) value of 0. The challenges identified as hindering access to and provision of RMNCH services during the pandemic include inadequate personal protective equipment, inadequate supply of essential medicine, and reduced funding for RMNCH services. The study concluded that COVID-19 pandemic had a significant negative impact on RMNCH in the four counties. The pandemic led to disruptions in health service delivery, resulting in reduced access to essential RMNCH services. Consequently, there was an increase in maternal and child deaths. Recommendations include strengthening health systems, improving access to essential RMNCH services, and providing necessary resources and support to healthcare workers for delivering high-quality care.