Public health emergencies, from Zika to COVID-19, have underscored the importance of addressing the needs of pregnant people and their infants. Recent events have underlined the critical role of mother-infant-linked longitudinal surveillance to characterize and assess the impacts of emerging, re-emerging, and persistent threats, including infectious diseases, on these populations. In partnership with state, local, and territorial health departments, CDC’s National Center on Birth Defects and Developmental Disabilities activated the Surveillance for Emerging Threats to Mothers and Babies Network (SET-NET) to capture information about pregnant people with laboratory-confirmed infection with SARS-CoV-2 (the virus that causes COVID-19) and their infants. SET-NET data were critical in recognizing the severe risks of COVID-19 during pregnancy, which ultimately informed clinical decisions and public health policy, specifically vaccine prioritization at the local, state, and national levels. This commentary describes the activation of SET-NET to monitor COVID-19 in pregnancy and highlights the experiences of health departments. We provide examples of how SET-NET findings informed COVID-19 prevention efforts and public health policy. Lastly, we identify opportunities to improve and advance surveillance efforts to protect the health of pregnant people and their infants in the United States from current and future threats.