OVERALL OBJECTIVES:

1. To assess the efficacy of a diet and exercise intervention before and/or during pregnancy in the prevention of GDM and its fetal complications in women with high diabetes risk.
2. To assess the cost-effectiveness of a diet and exercise intervention in the prevention of GDM from a socio-economic point of view. To find out whether the intervention can be used to reduce health care costs due to GDM and T2DM.
3. To determine the long-term effectiveness of the above-mentioned lifestyle intervention in the reduction of T2DM incidence among women with prior GDM and their offspring

STUDY SUBJECTS Group 1: Women planning pregnancy with a history of diet/insulin-treated GDM or BMI >30 kg/m2. N= 250 + 250.

Group 2: Women in early pregnancy with a history of diet/insulin-treated GDM or BMI >30 kg/m2. N= 250 + 250

METHOD The Finnish multi-center randomized controlled intervention trial started in the maternity hospitals of Helsinki and Uusimaa District Area 1/2008 and in the South-Karelia Central Hospital in Lappeenranta in 9/2008. 1000 women at high GDM risk will be recruited. Half of the subjects are randomized into the intervention group and the other half act as controls receiving only standard antenatal care in addition to the laboratory tests taken and questionnaires administered by the RADIEL study.

The active intervention arm of the study will be carried out in a structured, standardized manner by diabetes nurses and nutritionists specifically trained for their tasks. The intervention includes:

1. Structured visits to diabetes nurse every 3 months before and during pregnancy as well as at 6 weeks, 6 and 12 months post partum. Visits include e.g. structured counseling on diet and exercise, setting of specific goals, follow-up of achievements, laboratory tests and measurements
2. Structured group visits to nutritionist at the moment of enrollment in the study, at the beginning of pregnancy as well as at 6 and 12 months post partum. Additional individual visits are booked if needed.
3. Services of physical activity advisors are provided by the study subjects' cities of residence free of charge to all who wish to receive extra counseling on exercise. If exercise goals are not met, study subjects book an appointment with the physical activity advisor.

LIFESTYLE TARGETS: 1.Weight: A weight loss of 5-10% before pregnancy if BMI > 25 and/or limited weight gain during the first two trimesters in pregnancy if BMI > 30. 2.Exercise: A minimum of 30 min. of exercise 5 times per week or 50 min. 3 times per week of moderate intensity exercise (Borg 11-15). Daily household and/or transportation physical activity. 3.Diet: Increased intake of vegetables, legumes, fruits and berries, whole grain and fiber, low-fat dairy, vegetable fats; and use of "plate model". Total energy intake: 1600-1800 kcal/day, with 40-50 E% carbohydrates, 30-40 E% fats, 20-25 E% protein.

MEASUREMENTS of maternal variables:

AT THE MOMENT OF ENROLMENT TO THE STUDY, and every 3 months before pregnancy:

(1) Waist circumference, blood pressure, pulse, weight, height (2) i.e. 2-hour OGTT, fP-insulin, fP-glucose, , GHbA1c, lipids, P-hCRP, P-IL-6, S-A1Glypr, leptin. (3) Background questionnaire (4) 15-D-questionnaire: health-related quality of life. (7) Food diary (2+1). Exercise diaries daily for one week.

PREGNANCY At the end of each trimester: (1) The same tests and measurements as in pre-pregnancy period. 2h-OGTT at H10-14 and at H24-28. (2) Questionnaire, 15-D questionnaire, EDPS (=Edinburgh post-partum depression scale) questionnaire for screening mood disorders at H10-13. (4) Food diaries (2+1), and exercise diaries daily for one week at H10-13 and H34-36.

POST PARTUM PERIOD (Groups 1-2) At 6 weeks, 6 and 12 months post partum: (1) The same follow-up tests and measurements as at the beginning. Lipids checked only at 12 months post partum. (2) 2-hour OGTT 6 weeks and 12 months post partum (3) Questionnaires at all visits. (5) Food and exercise diaries at 12 months post partum.

MEASUREMENTS of child's variables at birth

(1) weight (2) height (3) head circumference (4) From delivery records: Mode of delivery, Apgar scores, any perinatal complications, operations, need of neonatal intensive care and length of hospital. (3) Laboratory tests from cord blood.

TIMETABLE Recruitment started in February 2008 and ended in autumn 2011 when about 800 subjects had been recruited to the study. Intervention will continue until 2014 (including pre- and postpartum periods). Long-term follow up of both mothers' and children's cohorts starts in 2014 and has been planned to continue up to 10 years postpartum. Data analysis starts in autumn of 2013 and results will be reported from 2014 onwards in international peer-reviewed journals.

Inclusion Criteria:

• obese (BMI > 30)
• previous GDM

Exclusion Criteria:

• Age < 18 years
• diabetes before pregnancy
• medication influencing glucose homeostasis
• hypertension
• multiple pregnancy
• physical disability
• substance abuse
• severe psychiatric disorders
• significant co-operation difficulties