Introduction:
The Menstrual Cycle is the second most important biological rhythm, next to the circadian one. [1] It is a series of physiological changes that occur in the ovaries and lining of the uterus beginning with the onset of menstrual flow on Day1. It consists of three phases: Menstrual Phase, Follicular Phase and Secretory/Luteal Phase. Menstrual Phase, lasting for 4-6 days, is defined as shedding of the thickened endometrium, a process known as menstrual bleeding. The Follicular or Proliferative phase continues until ovulation, lasting for about 7 to 14 days and is the period when follicles are grown under the influence of hormones. The Luteal Phase begins at ovulation and continues until the onset of menstrual flow, typically day 15 through 28. [2, 3]
Balance, as an essential neuromuscular function in human daily life and sports activities, can be defined as central nervous system input from proprioceptive, vestibular and visual afferent nerve signals, with analysis of signal integration [4]. It involves a combination of stability and postural orientation, being necessary for maintaining a position in space, moving in a controlled and coordinated fashion, and carrying out functional activities of daily living.[5]
Henkin RI in 1974 reported changes in somatic sensory processes during the menstrual cycle suggesting that hormones which regulate the menstrual cycle, may influence sensory acuity during the phases of the menstrual cycle. This study showed changes in taste, smell, hearing, light touch, and 2-point discrimination in the follicular phase of the cycle and suggested that estrogen may enhance sensory acuity during the follicular phase while progesterone release in luteal phase may lessen acuity. [6]
It is therefore imperative to gain a better understanding of the effect of the Menstrual cycle on balance. The aim of this study was to assess if balance score gets affected in Menstrual Phase Vs Late Follicular Phase of the reproductive cycle.
Methods
2.1: Participants: Thirty normal and healthy females from a reputed institution/setup were recruited for the study according to the inclusion criteria. Females with a regular menstrual cycle from the last three months, of age between 18-25 years and a normal BMI of 19-25 kg/m2, with no smoking history as it can affect the outcome of the study were included with informed consent. [7–11]. Females with any history of gynecological/reproductive disease (e.g. PCOD), treatment or surgical procedures, or irregular menstrual cycle, taking any medications/drugs/painkiller intake or hormonal treatment during menstrual phase or otherwise, at least 3 months before study initiation were excluded from the study. [10,11]. Pregnant women and females with history of visual or vestibular system disorder, having any type of neurological /cognitive impairment/musculoskeletal disorders/injury that can affect the outcome of the study were also excluded.[11,12]
2.2: Procedure and design: After explaining the procedure of this study and taking informed consent, they were asked to complete a data collection form. Subjects were asked history (date) of their last menstrual cycle and date of next expected menstrual cycle/reproductive cycle. The subjects’ parameters for balance (GBS) were collected two times, in two different phases of menstrual cycle i.e. they were assessed at two instances i.e. Menstrual Phase: When the data was collected on Day1 or Day 2 of menstrual phase/cycle and Follicular Phase: When the data was collected between Day10 to Day 12 of Reproductive cycle. (i.e. 10th -12th day of day 1 of Menstrual cycle).
On Day 1-2 of the menstrual cycle, the Global Balance Score was taken. On the Phyaction software, the Exercise program was set up for standing position with bilateral feet, at 40 cm diameter, straight board heading with Line profile done at Level 5. After Trial of 30 seconds, balance was again tested for one minute, which was used for results. During the test, they were asked to try maintaining the natural standing center of gravity without moving while keeping eyes open and instructed to keep herself balanced with the indicator in the center of the target on the screen [3] Global Balance Score was noted and its significance was explained to the subject i.e. the lower the Global Balance Score, the better the ability of the subjects to maintain the center of gravity. The same procedure was followed on Day 11-12 of the Follicular Phase of the same subject.
|
VARIABLE |
Mean |
Standard Deviation |
|
Age (yrs) |
21.043 |
0.9760 |
|
BMI |
21.352 |
2.6108 |
Table 1 Mean Age and BMI of subjects
Figure 1 – Subject performing Balance Score Assessment Test
Statistical Analysis
The Statistical analysis was performed using the statistical package SPSS. Paired t-test and Shapiro-Wilk test were used for comparing the values of GBS between Menstrual phase and Late Follicular phase. Data were assessed by a Shapiro-Wilk test for the normality of the distribution scores and all scores demonstrated normal distribution. The effects of menstrual phases on balance, as measured via Global Balance Score, was assessed using paired t-tests. Level of significance was set at p<0.05.
Results
3.1: Demographic characteristics of the subjects are demonstrated in table 1. Mean and standard deviation of the subjects were calculated for age and BMI parameter and the Mean age was found to be in the range 18-25 years .
3.2: As shown in table 2, p-value was found to be 0.59 which is non-significant. i.e. there is no change in Global Balance Score in Menstrual Phase vs late Follicular Phase of reproductive cycle.
|
VARIABLE |
Mean |
Standard eviation |
t-value |
P-value |
|
Menstrual Phase |
19.943 |
9.0472 |
1.992 |
0.59 |
|
Follicular Phase |
16.483 |
8.3002 |
Table 2 Comparison between Menstrual Phase and Follicular Phase
Figure 2 Comparison of Mean ± SD of Global Balance Score in Menstrual Phase vs Late Follicular Phase of reproductive cycle.
Discussion
23 subjects were included in this cross-sectional observational study to determine whether there is any significant difference in balance score in Menstrual Phase vs Late Follicular Phase of reproductive cycle. This was assessed by computerized Balance Trainer (Phyaction Balance) consisting of a software in computer that records Global Balance Score connected to Balance Board. The main finding of our study has shown non-significant results between Global Balance score in Menstrual Phase vs Late Follicular Phase.The influence of hormonal variations during the menstrual cycle on postural control is less investigated. There are only a few studies depicting the relation between Postural Balance and Menstrual Cycle and the results of various other studies are quite variable.
The results of present study show that Balance Score does not get affected in Menstrual Phase or Late Follicular Phase. These corroborate with Hayley Erickson et al., who also found that hormone fluctuations during the menstrual cycle did not affect ankle laxity or dynamic postural control. Dynamic postural control was assessed with the posteromedial reaching distance of the Star Excursion Balance Test. [13]
Christina Friden from Karolinska University, Sweden in 2004 studied Neuromuscular performance and balance during the menstrual cycle and the influence of premenstrual symptoms. Subjects were studied during three consecutive cycles and for each phase within the menstrual cycle. Balance was measured on an ankle disc placed on a Statometer and an AMTI Force Platform. There was no significant difference in the two – legged stance, either with Eyes Open or Eyes Closed, between the different phases of the menstrual cycle. As seen in our study they too found no significant correlations between hormone levels and measurements of postural control in the respective phase. [14] A study by Bruce D. Beynnon et al. obtained the same results in which women presented with greater knee and ankle laxity when compared to men. However, there was no relation to hormonal alterations i.e. there was no relationship between estradiol and progesterone fluctuation and ankle and knee joint laxity. [15]
Jerrold Petrofsky et al. in 2015 studied balance control during the menstrual cycle. There was no difference in sway during menstrual phase but impaired balance was observed at the day of ovulation due to increase in plantar fascia elasticity associated with increased levels of estrogen. However, there was no change in balance control during menstrual phase and late follicular phase and hence, results agree with our study. [16]
Also, there are some evidences to suggest that fluctuating levels of estrogen may result in changes in knee laxity due to alterations in the cellular metabolism of the ACL leading to increased risk of ACL injury.[17]
Elisabeth Livingstone et al studied the effect of menstrual cycle on musculotendinous stiffness and knee joint laxity. The result of their study demonstrated no statistically significant effect of the menstrual cycle on anterior knee laxity.[18] Similarly Karageanes and Blackburn also demonstrated no significant change in anterior knee laxity across the four phases of the menstrual cycle and furthermore, there was no significant change in knee laxity following exercise.[19]
However, there are few studies whose results do not corroborate with our results. Study by Darlington demonstrated the effects of menstrual cycle on postural stability but not on optokinetic function. It concluded that menstrual cycle significantly affects Lateral sway but no significant effect on gaze-holding, optokinetic nystagmus slow phase velocity, amplitude or frequency.[20]
Conclusions
Thus, looking at our results, one can presume that hormonal changes during different phases of the menstrual cycle do not cause significant alteration in balance scores.
Conflict of Interest
The authors declare there is no conflict of interest regarding publication of this article.
Author Contributions
All the authors have equally contributed for the study.
Funding
No Funding received for the research.
References
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