Mapping current evidence and knowledge gaps in gestational diabetes mellitus in Vietnam and Vietnamese diaspora: a scoping review.

Gestational diabetes mellitus (GDM) is an increasing public health concern among Vietnamese women. However, evidence across Vietnam and Vietnamese diaspora populations remains fragmented. Reported in accordance with the PRISMA-ScR guideline, this scoping review mapped available evidence on GDM among Vietnamese-origin women from database inception to November 2025 to inform future research and culturally responsive care. English and Vietnamese literature was searched across international databases, national repositories, and grey literature. Seventy-six eligible studies were included and synthesised descriptively. In Vietnam, the sample-size-weighted average prevalence of GDM was 23.24%, with substantial variation between 2010 and 2024. Consistent candidate risk factors included advanced maternal age, higher pre-pregnancy body mass index, family and obstetric history, diet-related factors, and physical inactivity. Studies also reported limited knowledge among pregnant women. GDM was associated with adverse maternal outcomes, larger birthweight, whilst maternal knowledge remained limited. Meanwhile, studies concerning the Vietnamese diaspora consistently reported a higher GDM prevalence and related obstetric complications compared with host-country populations. However, diaspora research lacked interventional trials. Existing literature is heavily hospital-based and methodologically heterogeneous. Future research must prioritise standardised screening protocols, community-based longitudinal cohorts, and controlled interventions to improve holistic GDM prevention and management across both Vietnam and migrant healthcare settings.