Three studies [17,18,22] used ‘diet only’, and one study [23] used ‘insulin only’ to treat GDM while others used combinations of treatments such as ‘diet with insulin if required’ [10,11,19,20,21,26,27,28,29,31,33,37], ‘diet and exercise with insulin, if required’ [6,12,32,34,36]. Here, INS is linked to gestational diabetes.