Methods

Randomised controlled trial.

Participants

Inclusion criteria: women with a previous history of GDM or a pre‐pregnancy BMI ≥ 30 kg/m², either planning pregnancy or pregnant at < 20 + 0 weeks’ gestation.

Exclusion criteria: age < 18 years; diabetes diagnosed before pregnancy; medications that influence glucose metabolism (e.g. oral corticosteroids and metformin); multiple pregnancies; physical disability; current substance abuse; severe psychiatric disorders and significant difficulties to co‐operate (e.g. inadequate Finnish language skills).

Interventions

Women randomised to structured counselling on diet and exercise or standard care.

Diet and exercise intervention

Women visited the study nurse every 3 months before and during pregnancy, and at 6 weeks, 6 and 12 months postpartum. Trained study nurses and nutritionists provided counselling, as below, and weight targets were set: 5% to 10% weight loss before pregnancy for women with pre‐pregnancy BMI ≥ 25 kg/m²; no weight gain during the first 2 trimesters for women with pre‐pregnancy BMI ≥ 30 kg/m².

Dietary counselling was based on national Finnish nutritional guidelines. The 'plate model' was used during the counselling sessions (filling half a plate with raw/cooked vegetables, one quarter with starchy carbohydrates, and one quarter with meat, fish, beans, eggs or other proteins). The aim was to achieve a total energy intake of 1600‐1800 kcal/day; 40% to 50% from carbohydrates, 30% to 40% from fats, and 20% to 25% from protein. Women were encouraged to increase intake of vegetables, legumes, fruits and berries; wholegrain and fibre; low‐fat dairy and vegetable fats. In the postpartum period, women received breastfeeding and infant nutrition counselling based on national recommendations. Every 3 months women filled in 3‐day food diaries. In addition to regular visits to the study nurse, women took part in structured group visits to a nutritionist, at enrolment, during the first trimester and at 6 and 12 month postpartum; with additional visits arranged if needed.

The aim of the physical activity counselling was to achieve a minimum of 30 minutes of moderate intensity exercise (exercise during which the woman becomes at least slightly out of breath and perspires but is still able to talk) 5 times/week or 50 minutes 3 times/week, and to adopt an overall active lifestyle. An individual exercise program was planned for each woman during the counselling visits, and modified as needed. Women also received pedometers, with a recommendation of at least 10,000 steps/day. Women had the option of attending guided exercise groups, or got tickets (e.g. to public swimming pooled once a week. Physical activity logbooks were used.

Standard care

Women received basic dietary and exercise information leaflets similar to those provided at primary health care centres at the time of enrolment. During pregnancy, they received usual health education provided at their local antenatal clinic.

Outcomes

Primary outcome: GDM.

Notes

Funding: "This study was funded by the Ahokas Foundation, the Finnish Foundation for Cardiovascular Disease, Special State Subsidy for Health Science Research of Helsinki University Central Hospital, Samfundet Folkhälsan, The Finnish Diabetes Research Foundation, the State Provincial Office of Southern Finland, and The Social Insurance Institution of Finland. The funders have not had any role in designing or conducting the study; in the collection, management, analysis, or interpretation of the data; in the preparation, review, or approval of the manuscript; and in the decision to submit the manuscript for publication".

Declarations of interest: "No potential conflicts of interest relevant to this article were reported".

Between February 2008 and November 2011, 788 women were recruited into the study. 235 were non‐pregnant and 493 pregnant during the first study visit. In the non‐pregnant and pregnant groups, 79.6% (women = 187) and 40.4% (women = 199), respectively, had a history of previous GDM.

To date, results have only been published for the women who were pregnant during the first study visit.

Last correspondence with Saila Koivusalo 01/12/2016 indicated manuscript relating specifically to non‐pregnant women with a history of GDM has not yet been published.