In developing countries, iron deficiency is a serious public health issue. In India, 52.2% of pregnant women are anaemic, according to the National Family Health Survey. Growth and development are negatively impacted, particularly in susceptible populations like infants and pregnant women [1]. Approximately one fifth of the world's population suffers from iron deficiency (ID). Pregnant women are susceptible to ID because of the increased need for iron during pregnancy brought on by the fetus's and placenta's growth as well as the mother's excessive red blood cell mass expansion [2]. A number of negative outcomes, including low birth weight, premature birth, intrauterine growth restriction, and maternal mortality, can also result from ID [3]. Unbalanced thyroid hormone levels (including overt and subclinical hypothyroidism and overt and subclinical hyperthyroidism) and positive thyroid antibody status are the hallmarks of thyroid dysfunction, a frequent endocrine condition in expectant mothers. According to studies, hypothyroidism affects 0.3% to 3% of expectant mothers [4]. Numerous negative consequences, including early delivery, miscarriage, neuro developmental abnormalities, and an elevated risk of autism and asthma in the kids, are caused by hypothyroidism [5].  Additionally, a higher percentage of pregnant women (about 18%) test positive for thyroid autoantibody (thyroglobulin antibody, TgAb,

or thyroid peroxidase antibody, TPOAb), which can also have a negative impact on pregnant women and their unborn children. Positive TPOAb elevated the incidence of postpartum depression by 1.5 times, according to a meta-analysis [6]. Positive thyroid antibodies during pregnancy increase the risk of preterm birth and increase the likelihood that the unborn child will have respiratory distress [7].  Pregnancy-related ID has been linked to thyroid dysfunction in a number of prior studies, as evidenced by increased "serum thyroid-stimulating hormone (TSH), and lower free triiodothyronine (FT3) and free thyroxine (FT4) concentrations, and lower total thyroxine (TT4) level" [8]. About 5% of those with thyroid dysfunction also have anaemia from ID, which is a common comorbidity [9]. The pathophysiology of thyroid dysfunction may be significantly influenced by ID, according to an increasing amount of research. ID is highly prevalent in individuals with thyroid disorders, including hypothyroidism and thyroid autoimmunity (TAI), which might affect the production and operation of thyroid hormones, according to several studies [10].

Aim of the Study

The study's goal is to determine whether iron deficiency anaemia and thyroid dysfunction during pregnancy are related.detail the materials and methods, present the results, and discuss their implications in the context of existing literature.

This is a Cross Sectional Observational Study conducted among 200 pregnant women who are attending antenatal OPD for routine checkup in a tertiary care hospital, central India.

Inclusion criteria:

• Pregnant women age ranged from 18-40 years
• Pregnant women coming for antenatal checkup during 1st Trimester
• Patients who given written informed consent for the study

Exclusive criteria

• Pregnant women with acute illness, recent history of blood transfusion, Renal and hepatic failure,
• History of thyroidectomy, History of radioactive iodine therapy, using drugs known to cause hypothyroidism
• Pregnant women with DUB or acute GI bleed
• Patients who not given consent for the study

A detailed history included patients particular, personal, family, menstrual and obstetric history of the patients in the proforma was obtained along with general, systemic and obstetrical examination findings. After proper counseling all the cases underwent routine antenatal investigations which included complete haemogram i.e. RBC, WBC, Hb%, Platelet count, PCV, MCV, MCH, MCHC. Along with these thyroid profiles for all the cases including serum TSH, Free T3, Free T4 was done.

The cases were called for antenatal checkups as per WHO criteria and in high risk cases more frequently. The study group was subjected to investigations as per WHO guidelines. They were followed up till delivery and 6wks postnatal.

In present study we have used trimester specific reference ranges for thyroid tests, reference ranges for iron deficiency anemia, hemoglobin cutoff for anemia as per ICMR and reference ranges for various indicators of Iron deficiency anemia [11-12].

The reports of the cases were assembled and compared to see the relationship between thyroid disorder and iron deficiency anemia in pregnancy. In addition to this incidence of thyroid disorder iron deficiency anemia in pregnancy was calculated

Statistical Analysis: Data was entered to in Microsoft Excel and the data analyzed by using Epidata software. Descriptive statistics like mean, percentage, standard deviation, and chi square test, t test were used. P value <0.05 was considered as statistically significant

Among 200 antenatal cases, 42 had increased thyroid stimulating hormone (TSH) of which 8 cases were diagnosed to have overt hypothyroidism and rest 34 cases had subclinical hypothyroidism.

The demographic details of each participant were collected. Majority of the women were 26-30 years age group followed by 18-25 years of age group. The mean age was 26.47±3.52 years. Most of them (44%) had education up to secondary school and had normal body mass index

Table 1: Demographic characteristics of the study population

Among total, 62 (31%) had developed iron deficiency anemia, among them 50 had mild anemia, 8 had moderate anemia and 4 had severe anemia as shown in graph 1

Graph 1: Distribution of iron deficiency anemia among study women

6.5% of pregnant women had overt hypothyroidism in anemic group as compared to 3.6% in non-anemic group. 35.5% in anemic group had sub-clinical hypothyroidism as compared to 27.5% in non-anemic group with statistically significant with p value <0.05.

Table 2 Thyroid status of among anemic and non anemic pregnant women

There was no significant statistical difference between Serum TSH, FT3, FT4 and severity of anemia with a p>0.05

Table 3: Comparison of TSH, FT3, FT4 with severity of anemia

It was found that serum FT4, FT3 and TSH were significantly associated with serum ferritin level (p<0.05).

Table 4:  Relationship between Serum ferritin and serum FT3, FT4 and TSH

worldwide as well as in India, and its prevention is a public health goal.

Majority of women selected for the study were between 26-50 years age group, with mean age was 26.47 years, which is similar in characteristics with respect to other studies conducted by Singh R et al [13] and Zimmermann et al [14].

We found that age and BMI levels were comparable between both iron deficient and non-iron deficient groups, in accordance with the Meher et al [15].

In existing study, the prevalence of iron deficiency anemia was 31%, which was comparable with the Chowdhury MD, et al [16] and Veltri et al [17], reported prevalence of IDA were 27% and 35% respectively.

We have found that the majority of the patients having mild anemia followed by moderate and severe anemia. Our finding was correlates with the study done by Muthulakshmi et al [18].

Current study observed that subclinical hypothyroidism was more common than overt hypothyroidism in both anemic and non anemic groups, which is in accordance with the Baghel et al [19] who also found subclinical hypothyroidism more common than overt hypothyroidism. Iron deficiency anemia affects thyroid metabolism by inducing alteration in common hypothalamo pituitary thyroid axis, reducing T3 binding to hepatic nuclear receptor or through anemia and lower O2 transport.

In our study there was statistically significant association between prevalence of anemia and hypothyroidism, in agreement with the Garofalo, et al [20] and Narayana, et al [21].

Correlation between Iron deficiency and hypothyroidism is likely due to impaired thyro-peroxidase (TPO) hemoprotein biosynthesis, as shown in a rat study in which Iron deficiency reduced TPO activity. RBC counts were decreased in hypophysectomised mammals and the RBC counts improved with administration of thyroid hormones.

A study done by Prabhavati et al [22] also concluded increased risk of anemia in untreated overt hypothyroidism in pregnant women.

We also found a statistically significant difference in TSH value in between anemic and non anemic groups. However there was no correlation between severity of anemia and TSH values. Similar studies by Kulkarni et al [23] and Anand et al [24] reported a negative correlation between TSH value and severity of anemia which is in contrast to our study.

The present study observed a positive correlation between FT4 and ferritin, and inversely correlation between serum TSH levels and ferritin with a significant p-value of <0.05, our results were concordance with the Gupta N, et al [25].

Since us anemia and thyroid profile was done at same time we could not identify the causal relationship.

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