Background
Rationale for the trial and for the choice of the interventions
Objectives
Methods
Design
Recruitment and eligibility
-
confirmed diabetes (two abnormal OGTTs), [57] or one OGTT with unequivocal values [abnormal fasting and 2 h plasma glucose values; fasting plasma glucose ≥140 mg/dl (7.8 mmol/L) or 2 h glucose ≥270 mg/dl (15 mol/L)];
-
current use of antidiabetic medication;
-
normal glucose tolerance (if not using insulin during pregnancy);
-
an indication that the trial interventions are not feasible, for example, due to relocation to a place distant from the trial site or a poor response in previous contacts (e.g., lack of interest in phone interviews);
-
a body mass index ≥ 40 kg/m2; and
-
health limitations or treatments (assessed by questionnaire) which would restrict the nutritional intervention or the ability to practice physical activity, affect glucose tolerance or limit participation or survival.
Baseline measurements and trial enrollment
Randomization
Intervention groups
-
✓ Control Group: Less intensive conventional care for women with prior GDM. This group receives a booklet containing instructions about diabetes prevention and materials based on current guidelines with recommendations for breastfeeding, physical activity and healthy eating. They are informed about the benefits of periodically checking their diabetes status and that such an assessment will be provided annually during the trial.
-
✓ Intervention Group: A more intensive program designed to promote and support healthy behaviors likely to prevent diabetes. In addition to receiving the above materials, women in this group receive participant-centered coaching focused on prolonging breastfeeding, weight control and a healthy life style with emphasis on the quality of their diet and physical activity. Coaching is primarily done by phone, and registration of weight and steps taken is encouraged.
Key aspects of the intervention
-
Promotion and support for exclusive breastfeeding for up to six months of life and partial breastfeeding thereafter for at least three additional months.
-
Stimulation and support for personally-monitored weight loss and maintenance with the goal of returning to pre-pregnancy weight and, for those overweight or obese pre-pregnancy, losing at least an additional 5 % of body weight. If this goal has already been achieved at randomization, the treatment goal will be a loss of 5 % of current body weight or that needed to achieve a BMI of 22.5 kg/m2.
-
Promotion of healthy eating, emphasizing avoidance of ultra-processed foods, limited intake of oils, sugars and processed meats, increased intake of foodstuffs in their natural state, regular intake of water and dairy products, and intake of coffee and tea without sugar or sweeteners.
-
Encouragement and support for a personally-monitored progressive increase in physical activity with an initial goal of breaking up extended bouts of sitting with ambulatory activity, reduction of sedentary behavior (defined as <5000 steps/day); and later striving to perform at least 150 min of moderate or vigorous physical activity/week (7500 steps/day with at least 30 min. taken at a cadence of 100 steps/min.) [75‐77].
Stage 1 | Stage 2 | Stage 3 | |
---|---|---|---|
8-12 weeks | 8 a 26 weeks | Up to close out | |
Weight control | Initiating weight loss (up to 2 kg/month while breastfeeding) when needed. | Achieving further weight loss to goal when needed/weight maintenance. | Maintaining weight (additional weight loss if needed). |
Goal: return to pre-pregnancy weight and, for those overweight or obese prior to pregnancy, loss of at least an additional 5 % of body weight. | |||
Healthy eating | Developing healthy eating. | Overcoming difficulties to sustain healthy eating. | Maintaining healthy eating. |
Active life style | Developing an active lifestyle. | Developing an active lifestyle. | Maintaining/enhancing an active lifestyle. |
Goal: breaking up extended bouts of sitting with ambulatory activity; reducing sedentary behavior (defined as <5000 steps/day). | Goal: increasing physical activity to at least 150 min of moderate or vigorous physical activity/week, or 7500 steps/day. |
Approach | Description |
---|---|
Motivational interviews | An initial 30–40 min session informs baseline results; evaluates motivation and self-efficacy; and sets individual goals to establish an initial action plan. Additional sessions occur during pre-defined clinic visits. |
Phone sessions | Phone sessions are the principal means of delivering the intervention. A minimal core curriculum will be covered, but the sequence and frequency of the sessions will be tailored to each participant’s needs. During weight loss, frequency may be weekly or bi-weekly, but in general, monthly sessions are planned for the first year. |
SMS texting | Texting is used for reminders of exams and monitoring of weight and steps. With the progression of the intervention, when phone contacts are reduced in frequency, texting will be used to maintain motivation and adherence. |
Group sessions (as needed) | Specific topics are addressed, focusing on aspects which most benefit from group interaction. Participants are invited to attend sessions as needed. |
Social activities (optional) | These optional activities include culinary workshops and group walks. |
Trial outcomes
Measurements | Times of measurement during follow upa
| Main outcomes |
---|---|---|
Exams | ||
75 g oral glucose tolerance test | 6 months, annual | |
Glycated hemoglobin | 6 months, annual | Diabetes [57] |
HDL-C, triglycerides | 6 months, annual | Metabolic syndrome [78] |
Weight | 6 months, annual | Weight loss/maintenance |
Height | ||
Blood pressure, heart rate (Omron 765CP, Omron, Kyoto, Japan) | 6 months, annual | Metabolic syndrome [78] |
Waist and hip circumferences | 6 months, annual | Metabolic syndrome [78] |
Abdominal height (Holtain-Kahn caliper, Seritex, Tinton Falls, NJ, United States) | 6 months, annual | |
Percent body fat (InnerScan BC-1500,Tanita) | 6 months, annual | |
Handgrip strength (Jamar hydraulic hand dynamometer); 6 min walking test; sit and reach test (Wells bench, Wood-WCS) | 6 months, annual | |
Accelerometry (ActiGraph WGT3X) | 6 months, annual | Reaching 7500 steps/day [75] |
Questionnaires | ||
Quality of life [62] | Annual | |
Depressive symptoms (Edinburgh questionnaire) [79] | 6 months, annual | |
Annual | ||
Sleep quality (Pittsburg questionnaire) [80] | Annual | |
Breastfeeding status | 6 months, 1 year | Duration of exclusive and overall breastfeeeding |
Dietary recall/registry | 6 months, annual | |
6 months, annual |
Follow-up
Activity | Recruitment for the trial and follow-up of those not entering the trial | Clinical trial | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Pregnancy | Perinatal period | Post-pregnancy period (weeks) | ||||||||||
Recruitment | Telephone contact | Trial preparation | Baseline measures | Follow-upa
| All women entering the trial | |||||||
Post-randomization follow-up (months) | ||||||||||||
Gestational weeks 20–40 | Pregnancy to 30 days postpartum | 4–104 | 8–104 | Up to 260 | 0 | 0–6 | 6–12 | 12–24 | 24–36 | 36–48 | 48–60 | |
Consents | x | x | ||||||||||
Entry | x | x | x | Trial randomization | ||||||||
Interviews/exams/chart reviews | x | x | x | x | x | x | x | x | ||||
Phone contacts | x | x | x | |||||||||
Baseline and follow-up measurements | x | x | x | x | x | x | ||||||
Material distributions | Breastfeeding folder 1; Pregnancy to postpartum booklet | Mail at birth: Breastfeeding folder 2 | Project folder | Preventing diabetes booklet | ||||||||
Intervention group | ||||||||||||
Motivational interviews | x | x | x | x | ||||||||
Phone sessions | x | x | x | x | x | x | ||||||
SMS texting | x | x | x | x | x | x | ||||||
Group sessions | As needed | |||||||||||
Social events | As needed | |||||||||||
Mailings | As needed |