Continuous glucose monitoring amongst pregnant women with early-onset type 2 diabetes

INTERVENTION: Recruitment visit: When women have expressed their wish to participate, they will be invited for the recruitment visit, when the following activities will be performed by the research team: • Checking inclusion and exclusion criteria • Written informed consent • Baseline socio‐demographic data collection • Relevant medical / obstetric history and present medical (diabetes, comorbidity, medication, and obstetric) information • Body weight and height, calculation of BMI • Early pregnancy HbA1c recorded (or performed if not previously done in this pregnancy) • Blood sample taken for metabolic phenotyping (C‐peptide, autoantibodies, genetic risk score) • Baseline questionnaire pack provided for participants to complete at home (either paper or electronically via link) • Masked Freestyle Libre 3 sensor insertion (ideally 2 weeks prior to randomisation) Women will have a small glucose sensor inserted under the skin by the clinical research team and will be instructed to wear it at home for up to 14 days. They will not be able to see the glucose information from this sensor. Randomisation visit: Ideally the sensor will be in place for 14 days, however if necessary to meet timelines, at least 3‐4 days of CGM data should be available prior to randomisation (prior to 16 weeks' gestation). At the randomisation visit, the following will be performed: • Masked CGM sensor upload & review (to confirm adequate baseline data available). Those randomised to the intervention arm will have access to the data from the masked sensor period following randomisation. CONDITION: Early‐onset type 2 diabetes in pregnancy ; Pregnancy and Childbirth PRIMARY OUTCOME: ; 1. Percentage time spent with maternal glucose levels within target range as recorded by CGM Time‐In‐Range (TIR 3.5‐7.8mmol/l) from 20 until 38 weeks’ gestation or until delivery, if delivery is earlier than 38 weeks’ gestation; 2. Neonatal unit admission or death (stillbirth/neonatal death) From randomisation to discharge after delivery (or 28 days post delivery if admission prolonged); INCLUSION CRITERIA: 1. Type 2 diabetes (T2D) 2. 16 years of age or over 3. Confirmed pregnancy < = 14 weeks’ gestation 4. HbA1c of > = 43 mmol/mol (6.1%) in pregnancy (< = 14 weeks’ gestation) 5. Willingness to use the study devices throughout the trial 6. Able to provide informed consent SECONDARY OUTCOME: ; 1. HbA1c & CGM mean glucose, GMI, frequency & duration of glycaemic excursions [%Time‐Above‐Range (=6.7 & =7.8mmol/L), %Time‐Below‐Range (=3.5 & =3.0mmol/l)], glycaemic variability (glucose SD, CV)] From 20 until 38 weeks’ gestation or until delivery, if delivery is earlier than 38 weeks’ gestation; 2. Hypertensive disorders from randomisation to discharge after delivery (or 28 days post delivery if admission prolonged); 3. Gestational weight gain from baseline (early pregnancy) to last visit prior to delivery; 4. Diabetes treatment (metformin & insulin use) From 20 until 38 weeks’ gestation or until delivery, if delivery is earlier than 38 weeks’ gestation; 5. Hospital admissions & duration of stay from randomisation to discharge after delivery (or 28 days post delivery if admission prolonged); 6. Severe hypoglycaemia, hyperosmolar hyperglycaemic state, and diabetic ketoacidosis episodes from randomisation to discharge after delivery (or 28 days post delivery if admission prolonged); 7. Gestational age at birth; 8. Birth weight for gestational age (SDS) (GROW customised birth weight, LGA birth weight >90th centile or SGA <10th centile) at Birth; 9. Mode of delivery at delivery; 10. Neonatal unit admission >24hrs (duration of stay, highest level care) at Discharge after delivery; 11. Adverse events (pregnancy loss <24 weeks, congenital anomaly (any), stillbirth, neonatal death) at Delivery; 12. Birth injury (spinal cord injury, clavicular, skull or bone fracture, shoulder dystocia, nerve palsy, subdural or intracerebral haemorrhage, hypoxic ischaemic encephalopathy) at Birth; 13. Neonatal morbidity (treatment for neonatal hypoglycaemia, respiratory distress requiring treatment, neonatal jaundice requiring treatment) at Discharge after delivery; 14. Feeding at hospital discharge (exclusive breast‐feeding / partial breast‐feeding / exclusive formula feeding) at Discharge after delivery; 15. Diabetes distress, anxiety & depression and treatment satisfaction using short questionnaires at Baseline & 32 weeks’ gestation; 16. Qualitative study to explore the acceptability, barriers, and facilitators for CGM use in T2D pregnancy at Baseline & 32‐36 weeks’ gestation; 17. Incremental cost per quality‐adjusted life year (QALY) at Randomisation to discharge after delivery;