Micronutrient deficiencies (MiNDs), often referred to as hidden hunger, arise when dietary intake is adequate in caloric content, but lacks of essential vitamins and minerals [1]. Although less visible than overt malnutrition, MiNDs can be equally detrimental, leading to persistent fatigue, impaired cognitive development, reduced immunity, and increased susceptibility to diseases [2], [3]. The World Health Organization (WHO) and United Nations Children's Fund (UNICEF) have established Global Nutrition Targets 2025 to address these nutritional challenges. Women of childbearing age and children are particularly vulnerable because of their heightened nutritional requirements during pregnancy, breastfeeding, and growth [4]. The WHO and UNICEF have incorporated nutritional security into their Sustainable Development Goals (SDGs) through the Global Nutrition Targets 2025 Initiative; however, progress has been limited, especially in low-middle-income countries (LMICs), where dietary diversity remains inadequate and health systems frequently fail to provide sufficient coverage [5].

Among the manifestations of hidden hunger, anemia during pregnancy is the most widespread and clinically significant. It is a heterogeneous disorder shaped by nutrition, infection, inflammation, socioeconomic conditions, and cultural practices [6]. Iron deficiency anemia (IDA) accounts for nearly half of all cases of anemia worldwide. However, deficiencies in folate, vitamin B12, vitamin A, and other micronutrients also play a substantial role, especially in resource-limited regions with restricted dietary diversity. Globally, around 38 % of pregnant women are anaemic, with prevalence rising to 50–60 % across South Asia and sub-Saharan Africa—several times higher than the 9–18 % reported in high-income countries [7], [8], [9]. The etiology of anemia varies across populations, reflecting dietary habits, infection prevalence, and lifestyle. In South Asia, vegetarian diets result in widespread vitamin B12 deficiency, whereas insufficient intake of green leafy vegetables and fruits contributes to folate deficiencies [10]. In sub-Saharan Africa, anemia is aggravated not only by poor diet but also by malaria, helminthic infections, and chronic inflammation [11]. Rural communities dependent on phytate-rich cereals face reduced bioavailability of iron and zinc, whereas urban populations, although often benefiting from food fortification, increasingly face obesity and chronic inflammation, which impair red blood cell production [12]. These variations underscore that anemia is not a uniform condition, but a multifactorial disorder shaped by complex biological and environmental interactions that differ between individuals.

India faces a significant challenge concerning maternal anemia, as highlighted by the National Family Health Survey-5 (2019–21), which indicates anemia in 57 % of women of reproductive age and 52 % of pregnant women [13]. In various states, including Uttar Pradesh and Bihar, approximately two-thirds of women are affected by anemia. National initiatives such as Anemia Mukt Bharat (AMB) and POSHAN Abhiyaan are designed to promote iron–folic acid (IFA) supplementation, deworming, and dietary improvements. However, compliance with IFA supplementation remains low, and the programmatic focus is still largely limited to iron and folate [14]. This limited perspective fails to consider other significant micronutrient deficiencies, such as vitamin B12, vitamin A, zinc, copper, and manganese, which may account for the persistent rates of anemia despite various interventions.

Micronutrients, in addition to iron, play crucial roles in hematopoiesis and maternal health. Folate (vitamin B9) is essential for DNA synthesis and red blood cell (RBC) production. Deficiency in this area results in megaloblastic anemia and increases the risk of neural tube defects in the fetus. Thiamine (vitamin B1) is essential for glucose metabolism, and its deficiency can disrupt folate metabolism and impair red blood cell production. Thiamine deficiency also contributes to oxidative stress and premature destruction of red blood cells, exacerbating anemia [15], [16], [17], [18]. Vitamin B12 (cobalamin) is vital for red blood cell formation and neurological function. A deficiency in B12 during pregnancy can lead to megaloblastic anemia and fatigue, with severe consequences for both maternal and fetal health [19], [20].

Iron, a key component of hemoglobin, is essential for oxygen transport, and its deficiency leads to iron-deficiency anemia, the most common form of anemia during pregnancy. The demand for iron increases during pregnancy, making pregnant women particularly susceptible to iron deficiency [21]. Zinc and copper are vital for various physiological processes, including immune function, DNA synthesis, and fetal development. These minerals play synergistic roles in iron metabolism and hemoglobin synthesis, and their deficiencies can further compromise red blood cell production and overall maternal health [22], [23]. Although less commonly discussed, Mn plays a role in bone formation and antioxidant defense, supporting tissue health and iron metabolism [24].

Despite the well-established biological roles of these micronutrients, very few community-based studies on LMICs have assessed their combined influence on anemia during pregnancy [25]. Most studies have focused on iron or folate levels, providing only a partial understanding of the causes of maternal anemia in LMICs. Moreover, the potential predictive value of low or borderline micronutrient levels in early pregnancy when interventions might prevent anemia later in gestation remains poorly characterized. Consequently, current public health strategies may not adequately address the multifactorial nature of anemia [26].

To address this gap, we investigated deficiencies in vitamins A, B1, B9, and B12 and iron, zinc, copper, and manganese among pregnant women. We compared the prevalence of these deficiencies between the anemic and non-anemic groups, hypothesizing that multiple micronutrient deficiencies confer a significantly higher risk of anemia than isolated deficiencies. By exploring these associations, we aimed to generate evidence to expand maternal nutritional strategies beyond iron and folate levels. A shift toward multi-micronutrient approaches could be more effective in reducing anemia prevalence and improving both maternal and fetal outcomes, particularly in underserved populations, where hidden hunger is widespread.