Healthy Habits During and After Gestational Diabetes

Background

Childhood obesity is a major global health burden, with increasing prevalence in many Asian countries, including Vietnam. However, health policies and programs in low- and middle-income countries (LMICs) often rely on evidence generated in settings that may not be directly applicable, limiting the effectiveness of interventions. Exposure to gestational diabetes mellitus (GDM) is associated with an increased risk of childhood obesity, while optimal early-life nutrition, particularly exclusive breastfeeding, may reduce this risk. In Vietnam, family members, including husbands, grandparents, and parents-in-law, have a substantial influence on infant feeding and childcare practices. These contextual factors highlight the need for family-based interventions to support healthy maternal and child behaviors following a pregnancy complicated by GDM.

Objectives

The Healthy Habits During and After Gestational Diabetes (VALID III) trial aims to evaluate the effect of the "Healthy Habits" family-based health intervention on improving infant feeding practices and childhood body composition among children born to women with GDM. The study will also assess the broader effects of the intervention on maternal and child health and wellbeing.

Study Design

This is a two-arm, parallel-group, superiority cluster randomised controlled trial with a 1:1 allocation of communes to either the intervention group (standard care plus the "Healthy Habits" intervention) or the control group (standard care plus access to a GDM management website). Pregnant women diagnosed with GDM between 24 and 28 weeks of gestation and their families will be recruited. Participants will be followed from pregnancy until 24 months after birth.

Intervention

The "Healthy Habits" intervention is a co-created family-based program delivered during pregnancy and continuing until 24 months postpartum. It includes counseling, peer support, digital health components, educational materials, and follow-up support focused on nutrition, infant feeding practices, physical activity, and GDM management, alongside routine clinical care.

Outcome Assessment

The primary outcome is the duration of exclusive breastfeeding during the first 180 days after birth. Secondary outcomes include the proportion of infants exclusively breastfed at 6 months, child fat mass index at 24 months after birth, process outcomes, and broader maternal and child health and wellbeing outcomes.

Inclusion criteria

• Confirmed GDM diagnosis in the current pregnancy according to WHO criteria and enrolled no longer than seven days after diagnosis.
• Gestational age at enrolment ≤ 28+0 weeks of pregnancy.
• Maternal age ≥18 years at consent.
• Pregnancy with singleton gestation
• Residence within the study catchment area.
• Language proficiency sufficient to complete consent and study procedures in Vietnamese.
• Capacity to provide informed consent and willingness to participate in all trial procedures, including randomisation

Exclusion criteria

• Pregestational diabetes (type 1 or type 2) diagnosed prior to this pregnancy.
• Severe chronic medical conditions and chronic severe mental health conditions likely to interfere with participation, safety, or outcome assessment (e.g., advanced cardiac, renal, hepatic disease; active malignancy; severe uncontrolled endocrine disease other than GDM, schizophrenia, active psychosis).
• Inability to provide informed consent .
• Pregnant women with multiple gestations.
• Pregnant women where it is biologically impossible for the woman to breastfeed, e.g., the woman has undergone bilateral mastectomy.
• Any other condition that, in the judgment of the investigators, makes participation inappropriate or infeasible, e.g., surrogate mother.