INS and gestational diabetes: This coincided with the introduction of the NICE guidelines in 2008 in the UK and the publication of a randomised trial looking at perinatal outcomes comparing metformin and insulin, which concluded that metformin, with or without insulin, is a safe and effective treatment for women with gestational diabetes who meet the standard criteria for starting insulin therapy.[36] The results of this trial were also referenced in one of the Norwegian guidelines and may explain why Norway also saw an increase in oral antidiabetic prescribing for the treatment of gestational diabetes from 2008.