With appropriate day-time carbohydrate intake and insulin dose, the 24 hour glucose levels and prevalence of night-time hypoglycaemia are comparable in breastfeeding new mothers and formula feeding new mothers with type 1 diabetes at the second after delivery diabetes control compared with the first after delivery diabetes control at Steno Diabetes Center.

Inclusion Criteria:

• Age between 18 and 45 years.
• Delivery of a single infant.
• Proficiency in Danish to read and understand the patient information sheet, questionnaires and to converse with the diabetes caregivers.

Exclusion Criteria:

• A diagnosis with severe mental or psychiatric barriers or a concurrent disease on the decision of the principal investigator

New mothers with type 1 diabetes