Glycemic Variations During the Menstrual Cycle in Women With Type 1 Diabetes

Inclusion criteria

• Females aged 18 to 50 living in Canada.
• Clinical diagnosis of type 1 diabetes or latent autoimmune diabetes in adults (LADA) for at least one year.
• Using insulin pump therapy, multiple daily injections or automated insulin delivery systems for at least 3 months.
• Using a continuous glucose monitoring (CGM) system.
• Having at least one menses in the last 40 days.
• Accepting to share CGM data with the research team and if applicable insulin pump data.This access will be limited to the study period.
• Having a smartphone or tablet to follow menstrual cycles.
• Stable weight (less than 5% variation in the last 3 months).

Exclusion criteria

• Using a hormonal contraception method that eliminates menses (Depo Provera, progestin intrauterine device, extented-cycle regimen with birth control pill)
• Using regular insulin (Entuzity U500, Novolin ge Toronto or Humulin R).
• Clinically significant nephropathy (eGFR < 30 ml/min/1.73m2, planned or on dialysis) or neuropathy (e.g., known uncontrolled gastroparesis) as judged by the investigator.
• Recent (< 6 months) acute macrovascular event (e.g., acute coronary syndrome or cardiac surgery).
• Anticipated therapeutic change (including change of insulin type and/or type of CGM sensor, insulin pump or AID (automated insulin device) system) between admission and end of the study.
• Anticipated change in contraception method or plan to begin or stop a contraceptive method.
• Anticipated need to use acetaminophen during the study period at a dose above 1g every 6 hours.
• Pregnancy (ongoing or current attempt to become pregnant)
• Breastfeeding
• Uncontrolled thyroid disease (TSH should be in target range and treatment stable for at least 6 weeks).
• Severe hypoglycemic episode within two weeks of screening
• Severe hyperglycemic episodes requiring hospitalization in the last 3 months.
• Current use of glucocorticoid medication (except low stable dose and inhaled steroids and stable adrenal insufficiency treatment e.g., Cortef®)
• Agents affecting gastric emptying (Motilium®, Victoza®, Ozempic®, Trulicity®, Byetta® and Symlin®) as well as oral anti-diabetic agents (Metformin, Prandase®, DPP-4 inhibitors) unless at a stable dose for 3 months and without anticipated change during the study.
• Current use of SGLT-2 inhibitors unless at a stable dose for at least 3 months, without anticipated change during the study and appropriate ketone testing is performed.
• Other serious medical illnesses which likely interfere with study participation or with the ability to complete the study by the judgment of the investigator.
• Anticipation of a significant change in exercise or diet regimen between admission and end of the study (i.e., starting or stopping an organized sport; planned significant diet change).
• Anticipated radiologic examination incompatible with CGM wear for more than 10 days between admission and end of the study (e.g., repeated MRI).
• In the opinion of the investigator, a participant who is unable or unwilling to complete the study.
• If taking medication for hypothyroidism, no change of dose (Levothyroxin) in the last 6 weeks.