Will a resource- and culturally-appropriate lifestyle intervention program in South Asian countries, provided to women with gestational diabetes after delivery, reduce the incidence of worsening of glycaemic status, in a manner that is affordable, acceptable and scalable?

The study will be conducted in 4 hospital sites • Colombo North Teaching Hospital, Ragama • Colombo South Teaching Hospital, Kalubowila • Negombo District General Hospital • De Soysa Hospital for Women

There will be two (2) study arms Consenting participants will be randomized through a central, computer-based randomisation service, and will be stratified by country, centre and use of insulin during pregnancy.

Intervention arm

Intervention will include up to 4 face-to-face group sessions reinforced by technology aided/mobile platform based messaging in the first six months. Face-to-face sessions will be delivered by a trained facilitator using the existing HeLP-her training program optimised for each country.

Eligible and consenting women will attend a local hospital in groups of 15-20 and will have baseline measures assessed prior to the commencement of the program. During session 1 they will receive a program specific user manual and over the following weeks work through the behavioural skills sessions with a health worker trained in the delivery of the program Following the face to face visits participants will receive reminders, motivational messages and small actionable behaviours delivered using mobile text messages and/ or video which we will adapt from a mobile phone/web application recently piloted in an Indian population (DPP-based Habits Program). Home visits and/or telephone calls will be utilised for participants who are unable to attend sessions to ensure all components are delivered.

All phases of the program focus on self-management through small feasible and sustainable changes by building knowledge and skills across 3 themes (1) simple healthy eating and moderate physical activity messages; 2) behavioural skills such as problem solving/goal setting/self-monitoring; and 3) enhancing internal motivation, self-efficacy and self-management.

Program intensification will be offered to women who gain weight by the 6 month time point; those who gain >2% of baseline weight (which accounts for transient weight fluctuations) will receive monthly phone coaching for the remaining 6 months, delivered by the trained facilitators.

The first encounter will take 3 -9 months after delivery when the women comes for an OGTT (oral glucose tolerance test)

The duration of the face-to-face sessions and number of text/video messages/home visits/telephone calls will be informed by the learnings from the formative phase.

Control arm Control group participants will be referred to their usual doctor for ongoing management, with no attempt made to influence this. Any abnormal OGTT results during follow up will be provided to the Patient and their doctor. This is entirely consistent with current usual care.

Absence of type 2 diabetes mellitus (T2DM) as confirmed by findings of Impaired Glucose Tolerance, Impaired Fasting Glucose, Normal Glucose Tolerance at the at 6±3 months post-partum OGTT (Oral Glucose Tolerance Test)

1. Place of residence outside the catchment of the treating hospital
2. Lack of access to a mobile telephone