Menstrual cycle irregularities and their relationship with HbA1c and insulin dose in adolescents with type 1 diabetes mellitus

Objective: To evaluate the prevalence and risk factors of menstrual cycle irregularities in adolescents with type 1 diabetes mellitus. Design: Prospective diary of menstrual cycle. Setting: Pediatric diabetes clinics and nearby schools. Patient(s): Adolescents with type 1 diabetes mellitus treated with multiple daily insulin doses (n = 56) and 56 healthy adolescents. Main Outcome Measure(s): Duration and variability of menstrual cycle. Result(s): Duration of the menstrual cycle was 48 +/- 39 and 32 +/- 7 days in girls with type 1 diabetes mellitus and controls, respectively. Oligomenorrhea (58.9% vs. 19.6%) and amenorrhea (10.7% vs. 1.8%) were more prevalent in girls with type 1 diabetes mellitus than in controls. Oligomenorrhea was observed in 53.3% of the girls with type 1 diabetes mellitus with optimal metabolic control. Girls with an HbA1c level of 7.6% to 8.9% exhibited increased cycle duration, menstrual cycle variability, and prevalence of oligomenorrhea compared with controls. Regression analysis showed that, for each point of increase in HbA1c, the menstrual cycle duration increased by 5.1 days. Cycle variability was associated with a higher daily insulin dose. Conclusion(s): Despite optimal metabolic control, a higher prevalence of oligomenorrhea was observed in girls with type 1 diabetes mellitus compared with controls. This is the first report to describe the high variability of the menstrual cycle in type 1 diabetes mellitus. HbA1c and insulin dose are important factors related to menstrual irregularities in type 1 diabetes mellitus. (Fertil Steril (R) 2010;94:1822-6. (C)2010 by American Society for Reproductive Medicine.)