Background
Menstrual cycle is the periodic physiological bleeding that characterises much of a woman’s reproductive life. It is hypothesized that this blood loss could predispose women to anemia.
Aim
Therefore, this study was designed to employ haematocrit values to assess for anemia in women within reproductive age at different phases of the menstrual cycle.
Materials and Methods
Fifty-one (51) apparently healthy, regularly menstruating female students of the University of Jos, Nigeria between the ages of 19-30 years were followed up in a single cycle. We determined the haematocrit values of the study subjects using the micro haematocrit method during the pre-menstrual, menstrual and post-menstrual phases of the menstrual cycle. Variations in Haematocrit (Hct) values at the different phases of the menstrual cycle were analyzed using paired student t-test.
Results
The average haematocrit value at pre-menstrual phase was 40.04 ± 1.89 (%), the menstrual was 37.40 ± 3.25 (%) and the postmenstrual was 39.70 ± 2.18 (%). The decrease in the mean haematocrit value observed at the menstrual phase when compared to the average values reported at premenstrual and postmenstrualphases was shown to be statistically significant (P < 0.005).
Conclusion
The data revealed that menstrual bleeding could be responsible for the decreased in the haematocrit values of the study participants.
Clinical significance
Although the decrease in haematocrit values may not necessarily lead to an anaemic state, it is important to maintain a regular check on this parameter to avoid eventual onset of anemia in menstruating women as a result of blood loss.
The menstrual cycle can be described as a series of carefully coordinated events that prepare a woman’s body for of the ovaries releases an egg- a process called ovulation [1]. At the same time, hormonal changes prepare the uterus for pregnancy [2].These hormonal changes divide the menstrual cycle into three phases; the menstrual phase, oestrogenic phase, and the progesteronic phase. If ovulation takes place and the egg is not fertilized, the lining of the uterus sheds through the vagina [3].
The average length of the menstrual cycle is 28 days although a variation of between 21-40 days is normal [4]. Some factors, including age, weight, diet, amount of physical activity, level of stress and genetics have been identified to affect the cycle and the amount of blood loss. The length of the menstrual cycle is counted from the first day of menstrual bleeding until the day of the next menstrual bleeding [3].
Menstrual bleeding could be heavy or light. Blood loss in menstruation ranges from 30-80ml [5]. The blood loss during menstruation results in a negative iron load in women and increases the risk for developing iron-deficiency anemia [1,6]. Anemia in adolescent girls has been shown to contribute to maternal and foetal mortality and morbidity later in life [7].This makes the measurement of Packed Cell Volume (PCV) across the menstrual cycle very important. Packed cell volume is also known as haematocrit. It is the percentage of total volume of whole blood occupied by packed red blood cells when a known volume of blood is centrifuged ata constant speed for a constant period [8]. The measurement of PCV is used as a screening test for anemia which could be as a result of blood loss or other underlying disorders [9].
This study, therefore, seeks to measure the haematocrit values of apparently healthy volunteer female students attending University of Jos who have a regular menstrual cycle, at different phases of the menstrual cycle; the pre-menstrual, menstrual and post-menstrual phase. This study aimed at assessing for anemia at the different phases of the menstrual cycle and show whether or not menstruation could be a predisposing factor to anemia in females.
Study area/Population
This study was carried out in the University of Jos, Plateau State, Nigeria. The study population comprises 51 healthy female adults in their reproductive years (19-30) having a regular menstrual cycle in the Department of Medical Laboratory Science, University of Jos, Nigeria.
Sampling/Study consent
After obtaining written informed consent from the study participants, we documented detailed history of each participant including the age, the age of menarche, the length of menstrual cycle and duration of menstrual flow.
Ethical clearance
The ethical clearance for this study was obtained from the Ethical Committee of Jos University Teaching Hospital (JUTH) Jos, Nigeria.
Inclusion and exclusion criteria
Non-pregnant women in their reproductive years (19-30), having regular menstrual cycles were included in the study. The presence of anemia, endocrinal, gynecological, for instance, excessive menstrual bleeding and haemostatic disorder (presence of any bleeding diathesis) and evidence of infection at the time of sampling were criteria for exclusion.
Blood sample collection/Experimental design
Three capillary blood samples were taken in a single menstrual cycle; during the menstrual phase, oestrogenic phase and progesteronic phase. The subjects were asked to report within 48 hours after onset of menses when the first sample of capillary blood was taken through finger prick under aseptic condition into a heparinised capillary tube. The second sample was taken similarly on the 9th day of the menstrual cycle, i.e. during the oestrogenic phase. The 3rd sample was taken on the 23rd day of the menstrual cycle, i.e. during the progesteronic phase.
All the samples were taken between 11:00 am - 12:00 noon to avoid diurnal variation and for consistency. Also, the samples were analysed immediately after collection to avoid any variations due to storage.
Laboratory methodology
The haematocrit values of participants were determined using the microhaematocrit method as described: Heparinized capillary tubes were two-thirds filled with blood from the capillary puncture and sealed on the dry end of the capillary tube with plasticine. The sealed tubes were placed in the Hawksley microhematocrit centrifuge and spun at a speed of 12,000 rpm for 5 minutes. The haematocrit or packed cell volume reading was obtained by adjusting the interface between the sealed end and the packed red cells column to zero on the micro-haematocrit reader. Haematocrit values were represented in % [10].
Data analysis/Statistical methods
The data obtained from the study were analyzed using the student’s paired T-test and presented in tables to compare values of PCV at the 3 phases of the menstrual cycle. Frequency tables of information gotten from the detailed history of the study participants are also presented to show the interaction between these factors and anemia through the menstrual cycle.
The description of study population including age distribution, the Age of Menarche (A.O.M), duration of Shortest Cycle (S.C) and Longest Cycle (L.C) and also the Duration of Menstrual Flow (D.M.F) of the subjects in clustered column charts are shown in Figures 1 to 5.
Figure 1: Distribution of study participants by age.
Figure 2: Distribution of study participants according to age of menarche (A.O.M) in years.
Figure 3: Outlook of study participants according to the shortest cycle (S.C) in days.
Figure 4: The spread of study participants according to longest cycle (L.C) in days.
Figure 5: Distribution of study participants according to duration of menstrual flow (D.M.F) in days.
Table 1 shows the mean and standard deviation of haematocrit values of study subjects at the premenstrual (40.04 ± 1.89), menstrual (37.40 ± 3.25) and postmenstrual (39.70 ± 2.18) phases of the menstrual cycle. Significant rise in haematocrit values were recorded in the premenstrual and postmenstrual phases of menstrual cycle when compared to the menstrual phase (p = 0.0001). However, the difference seen between the premenstrual and postmenstrual PCV values was not significant (p = 0.4070).
The Phase of Menstrual cycle
|
Mean ± SD
|
T-test value
|
P-value
|
Pre-menstrual
|
40.04 ± 1.89
|
4.9677
|
0.0001
|
Menstrual
|
37.40 ± 3.25
|
4.3664
|
0.0001
|
Post-menstrual
|
39.7 ± 2.18
|
0.8327
|
0.407
|
Table 1: The Mean and standard deviation of haematocrit values of study subjects at different phases of menstrual cycle.