Vitamin D deficiency has been linked to a variety of health consequences during pregnancy, and is a global public health concern. In this hospital based case control study conducted on pregnant women, our main aim was to find the association between Vitamin D status and iron deficiency anemia during pregnancy. We found maternal serum Vitamin D concentrations were significantly less in women affected with anemia as compared to normal pregnant women (mean: 19.61ng/ml in case group vs 29.43ng/ml in control group). Our results are in line with recent studies suggesting a strong association of low Vitamin D levels with anemia in pregnant women. Several studies reported low maternal vitamin D levels may be a risk factor for gestational anemia[19–23].
There are various possible explanations for the link between vitamin D deficiency and maternal anaemia. Calcitriol, the active form of vitamin D, may upregulate erythropoietin receptor expression on erythroid progenitor cells and may have a proliferative impact on erythroid burst generating units, which is synergistic with erythropoietin[24, 25]. Calcitriol has an essential part in the immune function control by reducing the activity of pro-inflammatory cytokines which could be critical to its involvement in anemia prevention[26]. Studies suggest an association between Vitamin D deficiency and upregulation of mRNA expression of hepcidin, a molecule resulting in decreased level of ferroportin responsible for iron absorption, which indicates adequate Vitamin D serum levels can provide additional protection against iron deficiency in pregnant women[6]. Vitamin D receptors have already been found in bone marrow, where its concentration is hundreds folds higher than in plasma.[7].
One of the most important findings of our study was the unexpectedly high prevalence of deficient Vitamin D levels among both groups (75% in case and 52.2% in control group). Hypovitaminosis D among North Indian pregnant women have also been widely reported[27–30]. The rationale might be owing to insufficient sun exposure, dark skin complexion and a lack of dietary calcium consumption, as Vitamin D synthesis initiates in the skin after sun exposure[31, 32]. High amounts of atmospheric pollution in Indian metropolitan cities could also be an important factor[33].
We also accounted for several parameters as a risk factor for maternal anemia where we reported the education status and socioeconomic status of the mother can also be a risk factor for anemia. This may be attributed to the fact that educated women belonging to middle socioeconomic status tend to prioritize self-care, actively engage in antenatal care, maintain a nutritious diet, supplement with iron and calcium, and take measures to prevent potential parasitic infections. The educational component makes the subject group more aware and responsive to new concepts and contents of public health campaigns, making them more likely to adopt good healthy living and treatment seeking behaviour. On the other hand, uneducated and economically disadvantaged mothers are expected to lack proper nutrition[34]. This explains education and socioeconomic status are linked with maternal anemia.
Our results show a positive correlation of the effect of iron and folic acid (IFA) supplementation on maternal anemia which are consistent with various other studies[35, 36]. Although India has incorporated iron and folic acid supplementation schemes for pregnant women since 1970, these programmes have been hampered by a variety of problems and supply and coverage restrictions[37]. These schemes were relaunched in 2018 as Anemia Mukt Bharat (AMB) Abhiyan to address basic difficulties such as programme finance, execution, and last mile delivery but still the prevalence of anemia was very high during pregnancy[38].
We discovered a link between regular milk consumption and anaemia. In contrast to our findings, coffee and milk have been recognised as possible iron absorption inhibitors, but only when high amounts of these items are ingested in the same meal as the iron[39]. This also shows that pregnant women are better aware of the need to take calcium and iron supplements not in the same meal. Still pregnant women should be concerned about their milk consumption as milk is an excellent source of protein and minerals like calcium, and it is linked to an increased birth weight[40].
A limitation of our study was the relatively small sample size. Therefore, further research involving a larger population size and considering long-term impacts is necessary to have a significant impact on public healthcare policy.