Inclusion Criteria:  Between 18 and 45 years of age (inclusive). A diagnosis of type 1 diabetes (T1D), as defined by WHO for at least 12 months. A viable pregnancy confirmed by ultrasound, up to 13 weeks and 6 days gestation. Currently on intensive insulin therapy (≥3 injections or CSII). Willingness to use the study devices throughout the trial. HbA1c level ≥48 mmol/mol (≥6.5%) at booking (first antenatal contact) and ≤86 mmol/mol (≤10%) at point of randomization. Able to provide informed consent. Have access to email.  Exclusion Criteria:  Non-type 1 diabetes. Any other physical or psychological disease which, in the opinion of the investigator, is likely to interfere with the normal conduct and interpretation of the study results e.g. untreated coeliac disease or untreated hypothyroidism. Current treatment with drugs known to interfere with glucose metabolism as judged by the investigator such as high dose systemic corticosteroids, non-selective beta-blockers and MAO inhibitors. Known or suspected allergy against insulin. Women with advanced nephropathy (eGFR <45), severe autonomic neuropathy, uncontrolled gastroparesis or severe proliferative retinopathy, as judged by the investigator, that is likely to interfere with the normal conduct of the study and interpretation of study results. Very good or very poor glycaemic control i.e. first antenatal HbA1c <48 mmol/mol (<6.5%) and current HbA1c >10% (>86 mmol/mol). Women who enter pregnancy with HbA1c >10% (>86 mmol/mol) may participate if they achieve HbA1c ≤10% (≤86 mmol/mol) before randomization. Total daily insulin dose 1.5 IU/kg. Severe visual or hearing impairment. Unable to speak and understand English.