Pregnant women with diabetes continue to have adverse pregnancy outcomes that are often related to hyperglycaemia.1 Tight glycaemic control has been recommended to reduce these adverse outcomes, but it is difficult to achieve these tight glycaemic targets. Part of the reason for this is the difficulty of matching exogenous insulin with glucose excursions, not only because of the difficulty estimating carbohydrate content in foods, but also the difficulty in matching the timing of insulin action with glucose excursions.