Reaching at-risk families with health and development information and connecting them to resources during pregnancy and throughout early infanthood remains a challenge for many health and early learning and development initiatives. This article showcases strategies used by Text4baby--a free mobile health program for pregnant women and mothers--to reach and engage Medicaid and uninsured populations through expanded content and outreach, including working with Medicaid agencies and health plans to support direct and opt-in enrollment. This article serves as a guide for others wishing to expand efforts to increase reach and engagement of hard-to-reach populations using mobile phones.