Maternal ExeRcIse Timing to Optimise Postprandial Glucose in Type 1 Diabetes

Inclusion Criteria: * Pregnant women and non-pregnant women with T1DM aged 20-40 years * Having a BMI of 18-29.9 kg/m2 at pre-pregnancy (pregnant women) or recruitment (non-pregnant) * Clinical diagnosis of T1DM, or/and multiple daily insulin injections for \>1 year, and/or using insulin pump therapy (open-loop). * Willingness to provide informed consent to participate in the MERIT1D study. * Being able to read and speak German, English or Spanish well enough to completely understand the instructions, provide informed consent and conduct the experimental procedures. Exclusion Criteria: * Having poor glycaemic control HbA1c\>10% (86 mmol/mol). * Recurrent severe hypoglycaemia; hospitalisation for diabetic ketoacidosis during the last year. * Women who smoke or drink alcohol frequently, or require complex diets. * Having polycystic ovarian syndrome, poorly controlled asthma/allergy, uncontrolled thyroid diseases or hypertension, diabetic ketoacidosis, hepatitis B, hepatitis C, HIV. * Having severe autoimmune/immunodeficiency, macrovascular, renal, or neuromuscular disease, or severe retinopathy or neuropathy. * Having any other cardiovascular, pulmonary, orthopaedic, neurologic, psychiatric, or terminal disease, or any other acute/chronic disorder that, in the opinion of the local clinician/researcher, would preclude participation and successful completion of the protocol, or that would directly influence the study results. * Use of any medication (e.g., steroids), that, in …