NCT01788527.

Trial name or title	Continuous glucose monitoring in women with type 1 diabetes in pregnancy trial (CONCEPTT)
Methods	Randomised controlled trial
Participants	Inclusion criteria: clinical diagnosis of type 1 diabetes and using daily insulin therapy for ≥ 1 year; age 18‐40 years; insulin regimen involving either the use of an insulin pump or multiple daily injections of insulin (≥ 3 shots/d) (women using premixed fixed doses of insulin at the time of enrolment not eligible); insulin regimen must be stable for ≥ 4 weeks (i.e. on multiple insulin injections or on insulin pump) prior to randomisation; no plan to be moving out of the area of the clinical centre during the next year, unless the move will be to an area served by another study centre; informed signed consent Specific inclusion criteria to the respective groups Pre‐pregnancy: women who are planning pregnancy and wish to optimise glycaemic control before conception Pregnancy: ≤ 13 weeks' and 6 days' gestation at time of randomisation: live singleton fetus; dating ultrasound done to confirm gestational age, viability and rule out multiples Exclusion criteria: type 2 diabetes; GDM; previous participation in the study; estimated GFR < 60 mL/min/1.73; presence of a significant medical disorder or use of a medication such as oral glucocorticoids that in the judgment of the investigator will affect the wearing of the sensors or the completion of any aspect of the protocol; inpatient psychiatric treatment in the past 6 months; subjects using premixed fixed doses of insulin at the time of enrolment Specific exclusion criteria to the respective groups Pre‐pregnancy: HbA1c < 7.0% or > 10.0% Pregnancy: HbA1c < 6.5% or > 10.0%; known current higher order pregnancies; known potentially major fetal anomaly
Interventions	Intervention: CGM with device Control: no intervention, standard of care, home glucose monitoring
Outcomes	Primary outcomes: glycaemic control in pre‐pregnant group (glycaemic control as measured by HbA1c at 24 weeks or at conception. If the woman becomes pregnant, HbA1c will be measured post‐confirmation of a positive pregnancy test and will contribute to the primary outcome); glycaemic control in pregnant group (glycaemic control as measured by HbA1c at 34 weeks' gestation. In women who do not progress to 34 weeks' gestation, the latest measured HbA1c will be used to contribute to the primary outcome) Secondary outcomes: time in target in pre‐pregnant group; time in target and HbA1c in pregnant group; hypertension; caesarean section; weight gain; area under the curve for blood sugars; severe, moderate, mild hypoglycaemia; glucose variability; length of hospital stay; infant birthweight > 90th centile; pregnancy loss; preterm birth; birth injury; shoulder dystocia; neonatal hypoglycaemia; hyperbilirubinaemia; respiratory distress syndrome; NICU admission; cord blood gas pH < 7.0; hyperinsulinaemia; composite fetal outcome; sum of skin folds > 90th centile; other anthropometric measures
Starting date	Study start date: March 2013 Estimated completion date: July 2017
Contact information	Denice Feig, Mount Sinai Hospital, New York
Notes	Estimated enrolment: 325