Anemia, characterized by a deficiency in the number or quality of red blood cells or their hemoglobin (Hb) content, remains a formidable public health challenge globally. The World Health Organization (WHO) estimates that anemia affects approximately 1.62 billion people, or 24.8% of the world's population, with non-pregnant women of reproductive age being one of the most vulnerable groups [1]. The condition's etiology is multifactorial, but iron deficiency is the most common cause, accounting for over half of all cases [2]. The clinical consequences of anemia are extensive, ranging from fatigue, impaired cognitive function, and reduced work capacity to increased susceptibility to infections and adverse pregnancy outcomes [3].

University students, particularly those in demanding professional courses like medicine, constitute a population at heightened risk for nutritional deficiencies. The rigorous academic curriculum, prolonged study hours, significant psychological stress, and consequent irregular dietary patterns can predispose them to conditions like anemia [4]. Female medical students face a "double burden" due to physiological iron loss through menstruation, which exacerbates the risk posed by their demanding lifestyle [5]. This chronic, cyclical blood loss makes them particularly susceptible to a negative iron balance if not compensated by adequate dietary iron intake.

The relationship between menstrual patterns and iron status is well-established. Menstrual characteristics such as the duration of flow, length of the cycle, and the volume of blood loss are critical determinants of an individual's iron stores [6]. Heavy menstrual bleeding (HMB), defined as blood loss exceeding 80 mL per cycle, is a leading cause of iron deficiency anemia (IDA) in premenopausal women [7]. Similarly, prolonged menstruation (menorrhagia) and frequent cycles (polymenorrhea) increase cumulative monthly blood loss, thereby elevating the risk of developing anemia [8].

Several studies have investigated the prevalence of anemia among female university students in various geographical locations. A study in Saudi Arabia reported a prevalence of 29.8% among female medical students [9], while research from India found rates as high as 45% in a similar cohort [10]. These studies highlight the scale of the problem but often provide limited detail on the specific menstrual patterns associated with anemia. While the link between HMB and anemia is known, there is a gap in comprehensive data correlating a spectrum of menstrual parameters (duration, cycle regularity, and self-perceived flow) with anemia status specifically within the context of the highly stressed medical student population. Understanding these specific correlations is crucial for designing targeted and effective screening and intervention strategies.

Therefore, this study was conceptualized with the primary aim of determining the prevalence of anemia in a cohort of female medical students. The secondary aim was to explore and quantify the association between anemia and various self-reported menstrual characteristics to identify high-risk patterns within this population.

The study population comprised all female medical students enrolled in the undergraduate (MBBS) program from the first to the final year. The sample size was calculated using the formula n = Z²P(1-P)/d², where Z (standard normal variate) = 1.96 for a 95% confidence interval, P (expected prevalence) = 0.30 (based on previous studies), and d (margin of error) = 0.05. The calculated sample size was 323. To account for potential non-responses, we aimed to enroll 350 students. A total of 300 students provided complete data and blood samples, yielding a response rate of 85.7%. Convenience sampling was employed to recruit participants.

Inclusion and Exclusion Criteria

Inclusion criteria were: (1) female medical students aged 18–25 years, and (2) willingness to provide written informed consent. Exclusion criteria were: (1) pregnancy or lactation, (2) known chronic diseases such as thalassemia, sickle cell disease, chronic kidney disease, or malabsorption syndromes, (3) recent history (within 6 months) of major surgery, significant trauma, or blood donation, and (4) current use of iron supplements or hormonal contraceptives for a pre-diagnosed medical condition.

Data Collection Tools and Procedure

Ethical clearance was obtained from the Institutional Ethics Committee before the commencement of the study. Participants were approached in lecture halls and common areas, and the study's purpose and procedures were explained.

1. Questionnaire: After obtaining written informed consent, each participant was asked to complete a pre-tested, self-administered, structured questionnaire. The questionnaire was divided into three sections:
• Sociodemographic Data: Age, year of study.
• Anthropometric and Dietary Data: Height and weight were measured to calculate Body Mass Index (BMI). A simple dietary frequency question was included to classify diet as vegetarian or non-vegetarian.
• Menstrual History: Age at menarche, cycle length (in days, categorized as <21, 21–35, >35), duration of flow (in days, categorized as <3, 3–7, >7), and self-perceived amount of bleeding (scanty, normal, heavy).
2. Hematological Analysis: A trained phlebotomist collected a 3 mL venous blood sample from each participant into an EDTA (ethylenediaminetetraacetic acid) vacutainer under aseptic conditions. The samples were immediately transported to the central laboratory and analyzed within two hours of collection for hemoglobin (Hb) concentration using a calibrated automated hematology analyzer (Sysmex XN-1000). Anemia was defined according to WHO criteria as an Hb concentration <12.0 g/dL.

Statistical Analysis

Data were entered into Microsoft Excel and analyzed using the Statistical Package for the Social Sciences (SPSS) version 25.0. Descriptive statistics were used to summarize the data and were presented as mean ± standard deviation (SD) for continuous variables and as frequencies and percentages for categorical variables. The Independent Samples t-test was used to compare the mean Hb levels between anemic and non-anemic groups. The Chi-square (χ²) test was used to determine the association between categorical variables (e.g., anemia status and menstrual patterns). A p-value of less than 0.05 was considered statistically significant for all tests.

A total of 300 female medical students participated in the study. The sociodemographic and general characteristics of the participants are presented in Table 1. The mean age was 21.3 ± 2.1 years, with the majority of students (65.0%) being between 21 and 25 years old. Participants were distributed across all years of medical study. The mean BMI was 22.5 ± 3.4 kg/m², with 72.3% of students falling within the normal BMI range (18.5–24.9 kg/m²). Approximately one-third (34.7%) of the participants followed a vegetarian diet.

Table 1: Sociodemographic and General Characteristics of Study Participants (N=300)

The overall prevalence of anemia (Hb <12 g/dL) in the study population was 25.3% (n=76). The remaining 74.7% (n=224) were non-anemic. The mean hemoglobin concentration for the entire cohort was 12.4 ± 1.5 g/dL. As shown in Table 2, the hematological parameters differed significantly between the anemic and non-anemic groups. The mean Hb level in the anemic group was 10.8 ± 0.9 g/dL, which was significantly lower than the 12.9 ± 1.1 g/dL observed in the non-anemic group (p<0.001).

Table 2: Comparison of Hemoglobin Levels between Anemic and Non-Anemic Groups

The association between menstrual patterns and the prevalence of anemia is detailed in Table 3. A strong and statistically significant association was observed between the self-perceived amount of menstrual bleeding and anemia. The prevalence of anemia among students reporting heavy bleeding was 59.2%, compared to only 19.6% among those reporting normal or scanty bleeding (χ²=31.5, p<0.001).

Similarly, the duration of menstrual flow was significantly correlated with anemia. Among students with a flow duration of more than 7 days, 40.8% were anemic, whereas the prevalence was significantly lower (14.3%) in those with a flow duration of less than 7 days (p=0.005). The length of the menstrual cycle also showed a significant association with anemia. Students with shorter cycles (<21 days, or polymenorrhea) had a higher prevalence of anemia (21.1%) compared to those with normal cycle lengths (8.9%) (p=0.021). The age of menarche did not show a statistically significant association with anemia status (p=0.452).

Table 3: Correlation of Menstrual Patterns with Anemia Status

This study provides crucial insights into the burden of anemia and its determinants among female medical students. The primary finding of our research is the high prevalence of anemia, affecting one in four students (25.3%). This finding is alarming for a population of educated, young adults who are the future torchbearers of the healthcare system. Our prevalence rate is consistent with findings from some regional studies, such as one conducted in Nepal which reported a prevalence of 28.6% among female medical students [11]. However, it is lower than rates reported in parts of India and Pakistan, where prevalences have been observed to be as high as 45% and 52%, respectively [10, 12]. This variation could be attributed to differences in socioeconomic status, dietary habits, genetic predispositions, and the diagnostic criteria used across studies. In contrast, studies from developed countries often report lower prevalences, emphasizing the role of nutritional and socioeconomic factors in the etiology of anemia [13].

The cornerstone of our study was the exploration of the link between specific menstrual patterns and anemia. Our results demonstrated a robust and statistically significant association between heavy menstrual bleeding and anemia, a finding that aligns perfectly with established physiological principles and existing literature [14]. Students who self-identified as having heavy menstrual flow were approximately three times more likely to be anemic. This underscores the critical role of excessive menstrual blood loss as a direct pathway to iron depletion and subsequent anemia. Chronic blood loss outpaces the body's ability to absorb sufficient iron from the diet, leading to a state of negative iron balance [7].

Furthermore, our study identified prolonged menstrual duration (>7 days) and short cycle length (<21 days) as significant risk factors for anemia. This is biologically plausible, as both conditions increase the total volume of blood lost over time. A woman with polymenorrhea, for instance, menstruates more frequently, leading to greater cumulative iron loss per year compared to a woman with a normal cycle length, even if the per-cycle blood loss is similar [8]. These findings highlight that it is not just the perceived volume but also the frequency and duration of bleeding that collectively determine the risk of anemia. This is a critical point for clinical assessment, suggesting that a detailed menstrual history is indispensable when evaluating a female patient for anemia.

The implications of these findings for the medical student population are particularly profound. Anemia is well-documented to cause symptoms such as fatigue, lethargy, dizziness, and shortness of breath, all of which can severely impair physical stamina and daily functioning. More critically for students, iron deficiency, even without overt anemia, is associated with impaired cognitive function, reduced attention span, and poor academic performance [15]. For medical trainees undergoing a mentally and physically demanding curriculum, the presence of untreated anemia could compromise their learning ability and overall well-being, potentially impacting their future professional competence.

This study has several strengths. We used a standardized, objective method (automated analyzer) for hemoglobin estimation, which is more reliable than older colorimetric methods. The inclusion of a detailed menstrual history allowed for a nuanced analysis of its correlation with anemia. However, certain limitations must be acknowledged. First, the cross-sectional design of the study does not allow for the establishment of causality. Second, menstrual characteristics were self-reported, which introduces the possibility of recall bias. The use of objective tools like the Pictorial Blood Assessment Chart (PBAC) could have provided a more accurate measure of blood loss. Third, this was a single-center study, which may limit the generalizability of our findings. Finally, our study did not include measurements of serum ferritin or other iron parameters, so we could not definitively confirm iron deficiency as the sole cause of anemia, although it is the most probable etiology in this demographic.

The prevalence of anemia among female medical students in our institution is substantial, representing a significant and under-recognized health concern. Our findings conclusively demonstrate a strong correlation between anemia and abnormal menstrual patterns, specifically heavy bleeding, prolonged duration of flow, and shorter cycle lengths. These menstrual characteristics serve as crucial clinical markers for identifying individuals at high risk. There is an urgent need for proactive measures, including routine screening for anemia, targeted health education focusing on menstrual health and iron-rich nutrition, and accessible counseling services for female students. Addressing anemia in this population is not only essential for their personal health and well-being but also a critical investment in the efficacy and resilience of the future healthcare workforce.

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