Abstract
BACKGROUND: Preconception health is essential for preventing premature birth, yet engagement in preconception care remains low. Internet-based interventions offer scalable solutions, but their effectiveness in this context is underexplored. OBJECTIVE: This systematic review aimed to describe the characteristics and designs of studies on internet-based interventions and evaluate their effectiveness in preventing premature birth among preconceptional women of childbearing age. METHODS: We searched MEDLINE, Embase, CINAHL, and the Cochrane Library for randomized controlled trials and quasi-experimental studies on internet-based interventions targeting premature birth prevention, covering publications up to December 2023 with no language or geographic restrictions. The search, conducted initially in February 2023 and updated in March 2024, followed PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines and was registered with PROSPERO (International Prospective Register of Systematic Reviews; CRD42021277024). Two reviewers independently screened studies, extracted data, and assessed the risk of bias using the revised Cochrane Risk of Bias tool. Due to heterogeneity in populations, interventions, and outcomes, a narrative synthesis was performed instead of a meta-analysis. RESULTS: From 3437 articles identified across 2 searches, 9 studies were included after excluding duplicates and ineligible papers. Studies, primarily from high-income countries (eg, 4/9, 44% from the United States), varied in design (4/9, 44% randomized controlled trials; 5/9, 56% quasi-experimental) and timing (5/9, 56% post 2020). The overall risk of bias was high in 6/9 (67%) studies, with only 1/9 (11%) rated low risk. Interventions, delivered via websites (4/9, 44%), conversational agents (3/9, 33%), or other platforms, significantly improved reproductive health knowledge in 3/9 (33%) studies but showed no consistent impact on self-efficacy (no effect in 2/3 [67%] studies assessing it). Behavioral outcomes, such as folic acid use and contraception initiation, were inconsistent across 5/9 (56%) studies, with significant effects in short-term (eg, 2/9, 22%) but not long-term interventions (eg, 2/4, 50% at 12 months). No studies directly measured premature birth as an outcome. CONCLUSIONS: Internet-based interventions showed mixed effectiveness across reproductive health outcomes pertinent to premature birth prevention, with notable gains in knowledge but limited success in altering behaviors. Given the small number of studies and the prevalent high risk of bias, these findings warrant cautious interpretation. Future research, including robust clinical trials, is essential to develop, evaluate, and disseminate effective and safe internet-based interventions for preconception care. TRIAL REGISTRATION: PROSPERO CRD42021277024; https://www.crd.york.ac.uk/PROSPERO/view/CRD42021277024.