Study design and participants
We conducted a randomized controlled trial in the Geneva University Hospitals (Switzerland) from February 2008 through April 2013. Women recently diagnosed with gestational diabetes using standard criteria11 and referred to a multidisciplinary team of diabetologists, specialised nurses, dieticians, obstetricians and midwives, were invited to participate. In our setting, from 2008 until 2010, GDM was diagnosed with a 50g OGTT (O’Sullivan test:12). A 50g OGTT ≥ 11 mmol/L was considered as gestational diabetes. If the result was ≥ 7.8 mmol/L but less than 11 mmol/L, a 100g OGTT was undertaken, and the results interpreted using the Carpenter and Coustan criteria 11. From 2011 onward, GDM was diagnosed with a 75g OGTT using the IADPSG criteria13.
Consenting women with a singleton pregnancy, a positive GDM test, and not treated with insulin were invited to participate. Exclusion criteria were age less than 18 years, insulin already started or prescribed during the first visit, pre-existing diabetes and a contraindication for physical activity.
The protocol complied to the principles of the Helsinki declaration, the study was approved by the Geneva University Hospital Research Ethics Committee (reference n° 07-080 MATPED 07-021) and registered at clinicaltrials.gov (NCT03174340). All participating women provided written informed consent.