Cardiac Autonomic Activity in Young Females with Primary Dysmenorrhea

Various studies have reported the effect of different phases of normal menstrual cycle on the autonomic control over the cardiac activity using heart rate variability (HRV) analysis. However, information on cardiac autonomic activity in young females suffering from primary dysmenorrhea (PD) is scant. Hence, the aim of the present study was to assess the HRV and blood pressure (BP) in different phases of menstrual cycle in women with PD and to compare these findings with eumenorrheic females. Sixty healthy unmarried female subjects (30 females with PD and 30 control subjects), in the age group of 18-25 years, having regular 28-32 days menstrual cycle were recruited for the study. Anthropometric measurements such as height, weight, BMI and WHR were measured. Blood pressure was measured with automatic blood pressure monitor and lead II ECG recordings were done to obtain HRV, during menstrual, follicular and luteal phases of menstrual cycle in both groups. The data recorded were subjected to time and frequency domain analysis. The results showed that dysmenorrheic women had significantly high BMI (P<0.05). Analysis of HRV during the different phases of the menstrual cycle between two groups revealed significantly increased (P<0.01) mean HR and significantly reduced (P<0.01) mean RR and RMSSD in all the 3 examined phases, SDNN significantly less (P<0.05) and systolic BP significantly higher (P<0.001) during the luteal phase in study group compared to control. Also, we observed a statistically significant decrease in TP and LF ms2 (P<0.05), HF ms2 & nu (P<0.01) in menstrual phase, HF ms2 (P<0.05) and HF nu (P<0.01) in luteal phase, while LF nu and LF-HF ratio were found to be significantly higher (P<0.01) in menstrual and luteal phases in women with PD compared to control group. This study has shown decreased HRV in the form of increased sympathetic tone and decreased parasympathetic activity in dysmenorrheic women which may be considered an important cardiovascular risk factor.