ESTROGEN LOWERS HEART RATE IN PRE-OVULATORY PHASE OF MENSTRUAL CYCLE IN WOMEN

Hormonal fluctuation in various phases of menstrual cycle may be an important regulatory factor of heart rate. Based on this proposition, an observational study was conducted in 81 women with normal reproductive health to find out the changes of heart rate in the pre-ovulatory (10-13^th day of menstrual cycle) and post-ovulatory phases of menstrual cycle. Data were analyzed using Pearson correlation and paired t-test. The test for correlation coefficient using t-statistics showed that the changes of heart rate between pre-ovulatory and post-ovulatory phases was statistically significant (r= 0.79, R²=0.63 and p<0.01). On the other hand, the paired t-test (2 tails) revealed that the heart rate was significantly decreased (t= 3.86, df=80, M_d=3.04 and p<0.01) in the pre-ovulatory phase when compared to the post-ovulatory phase. It is well documented that both estrogen and progesterone level are found to have moderate in luteal phase in relation to the pre-ovulatory phase during LH surge or peak estrogen level and it is approximately 10 times just 10-12 hours before ovulation. From the endocrinological view point, it can be concluded that the estrogen may have the heart rate lowering effects in pre-ovulatory phase in the study subjects.