[Glycemic changes during menstrual cycles in women with type 1 diabetes]

To determine frequency of women with type 1 diabetes showing menstrual cyclic changes in glycemia, analyze their clinical characteristics, and assess the pattern of glycemic changes.

We analyzed glucose meter readings along 168 menstrual cycles of 26 women with type 1 diabetes. We evaluated mean glucose, mean glucose standard deviation, mean fasting glucose, percentage of glucose readings>7.8 mmol/L and<3.1 mmol/L, and mean insulin dose in 4 periods for each cycle. A woman was identified as having cyclic changes when mean glucose rose from early follicular to late luteal in two-thirds of her menstrual cycles.

A percentage of 65.4 of the women had cyclic changes. Characteristics of women with and without cyclic changes, including self-perception of glycemic changes, were similar with exception of age at diabetes diagnosis (22.5 [7.5] vs. 14.4 [9.5] years; P=.039). In women with cyclic changes mean percentage of glucose readings>7.8 mmol/L rose from early follicular (52.2 [16.3] %) to early and late luteal (58.4 [16.0] %, P=.0269; 61.0 [16.9] %, P=.000).

Almost two-thirds of women with type 1 diabetes experience a menstrual cycle phenomenon, attributable to an increase in hyperglycemic excursions during the luteal phase. Enabling women to evaluate their weekly mean glucose from their meter and exploring the causes of hyperglycemic excursions during luteal phase should ensure more accuracy when giving instructions for diabetes management in women with premenstrual hyperglycemia.