OBJECTIVES: Ten National Children's Study (NCS) study locations with diverse demographic characteristics used an enhanced household-based recruitment (EHBR) approach to enroll preconceptional and pregnant women. Study centers used different types and dosages of community outreach and engagement (COE) activities and supplemental strategies. The goal of the study was to determine whether variability in enumeration and recruitment outcomes correlated with study location characteristics or types and dosages of COE activities (number of COE events, number of advance household mailings, total media expenditures, and total COE expenditures). METHODS: Each of the sites provided data on COE activities, protocol implementation, supplemental recruitment activities, location demographic characteristics, and enumeration/recruitment outcomes. RESULTS: COE activities varied across sites in breadth and scope. Numerous strategies were used, including media advertising, social media, participation in community-wide events, presentations to stakeholders, and creation of advisory boards. Some sites included supplemental recruitment efforts. EHBR sites enrolled 1404 women at the initial pregnancy screening. No significant relationships were found between study location demographic characteristics or between the types and dosages of COE activities and recruitment outcomes. CONCLUSIONS: Probability sampling for a long-term study requires a positive image with stakeholders and within communities; this requirement may be especially true for door-to-door recruitment. EHBR sites successfully recruited a representative sample of preconceptional and pregnant women. Sites reported implementing similar COE activities but with varying dosage and cost; however, analyses did not support a benefit of COE strategies on study recruitment.