Background: The importance of early identification for infants and young children with developmental delays is well established. Poor follow-up on referrals, however, undermines the effectiveness of early intervention programmes. Objectives: To identify factors, including text message reminders, that influence follow-up adherence for early intervention after developmental screening in primary health care. A secondary objective surveyed reasons for follow-up default. Methods: The PEDS tools were used to screen 247 high-risk children. A risk assessment questionnaire was completed with caregivers whose children were referred for speech-language and/or occupational therapy (n=106, 43%). A quasi-experimental correlational study was employed to identify risk factors for defaulting on appointments. A thematic analysis of telephonic interviews was also employed to determine reasons for follow-up defaults. Results: Follow-up adherence was 17%. Participants who were never married, divorced or widowed were 2.88 times more likely to attend a follow-up appointment than those who were married or living together (95%, CI 0.97-8.63). Text message reminders did not improve follow-up. More than half (58%) of participants who defaulted on appontments could be reached for telephonic interviews. Interviews showed that 87% of participants were unconcerned about their child’s development. Other reasons for defaulting were employment, logistical issues, other responsibilities and forgetfulness. Conclusion: Follow-up adherence for early intervention services following a positive primary health care screen was poor. Increased awareness and education regarding the importance of development for educational success is needed.