MON-577 - Glycemic Variability Across the Menstrual Cycle in Women With Type 1 Diabetes: The Impact of Menstrual Symptoms

Background:
Glycemic variability across the menstrual cycle phases has been reported in women with type 1 diabetes (T1D). However, findings remain inconsistent, and the association between menstrual-related symptoms and glucose levels is not well established. We aimed to evaluate continuous glucose monitoring (CGM)-derived metrics across menstrual phases and explore the association with menstrual-related symptoms.

Methods:
This prospective observational study enrolled 13 women with T1D, contributing 32 menstrual cycles. Participants were followed for three consecutive cycles. Patients with irregular cycles, pregnancy, breastfeeding, prior gynecologic surgery, or hormonal contraception use were excluded. Participants completed cycle-specific surveys capturing menstrual-related symptoms. Comprehensive CGM data analyses were conducted during follicular and luteal phases, and CGM-derived metrics were compared by menstrual phases and menstrual-related symptoms.

Results:
Mean age was 27±10.5 years, diabetes duration 13±10.2 years, and HbA1c 8.62±2.7%. Overall, no significant differences were observed in CGM metrics between follicular and luteal phases. However, among women reporting menstrual-related fatigue, average sensor glucose was higher during luteal phase compared to follicular phase (220.8 vs 210.5 mg/dL, respectively, p=0.03). Likewise, time above range >250 mg/dL was higher during luteal vs follicular phase (31.2% vs 27.5%, p=0.03). Furthermore, women with menstrual-related mood swings, luteal phase was associated with higher average sensor glucose than follicular phase (209.1 vs 196.4 mg/dL, p=0.03), higher time above range >250 mg/dL (28% vs 23.1%, p=0.04), and lower time in range (44.9% vs 51.4%, p=0.03). No significant differences in CGM-derived metrics between luteal and follicular phases were noted in women without menstrual-related symptoms.

Conclusion:
Menstrual-related fatigue and mood swings are associated with worse glycemic control during the luteal phase in women with T1D. Symptom-based stratification may be important in identifying women with T1D who could benefit from individualized diabetes management across the menstrual cycle. Larger studies are needed to confirm these findings and guide targeted interventions.

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