Thyroid dysfunction is the second most frequent endocrine condition during pregnancy, following diabetes. Recently, it has become the most sought-after research field in clinical endocrinology. Thyroid function assessment during pregnancy is important due to its impact on foetal and mother outcomes. Thyroid physiology changes during pregnancy and can be reversed after birth. High thyroxine-binding globulin (TBG), renal iodine loss, changed thyroid hormone metabolism, and altered iodine transport to the placenta are all contributing causes. These alterations enable the maternal thyroid gland to handle greater physiological demands[1].

During pregnancy, thyroxin (T4) and triiodothyronine (T3) synthesis increases by up to 50%, increasing a woman's daily iodine requirement & TSH levels fall, particularly in the first trimester[2]. Since Human Chorionic Gonadotrophin (HCG) is thyrotrophic, high levels during the first trimester lead to lower TSH levels, resulting in lower cut-offs. Pregnancy stress can cause overt disease in women with insufficient thyroid reserves[2]. Adverse pregnancy outcomes due to thyroid dysfunction include miscarriage, pregnancy-induced hypertension (pre-eclampsia), placental abruption, anaemia, post-partum haemorrhage, and increased foetal morbidity and mortality[3].

Pregnant women often have hypothyroidism, but detection rates in developing countries like India have not kept level with the problem's occurrence [2]. The prevalence of overt and subclinical hypothyroidism during pregnancy in India ranges from 3 to 4.58% and 6.47 to 9%, respectively.5, 6 About 0.4% to 1.7% of pregnancies are complicated by overt hyperthyroidism, and 0.4% to 0.7% by subclinical hyperthyroidism[1]. Early identification and treatment of hypothyroidism might mitigate the burden of poor foetal and mother outcomes during pregnancy[2].

Pregnancy-related hyperthyroidism is less frequent than hypothyroidism. About 1-5% of neonates may have neonatal Graves' illness, which is caused by the mother's TRAb being transferred to the foetus [3].

Anaemia is a significant global public health issue that disproportionately affects young children, menstrual adolescent girls and women, and pregnant and postpartum women. According to the World Health Organisation, 37% of pregnant women are anaemic globally[4]. Anaemia has been classified according to WHO guidelines, with a haemoglobin concentration of <11 g/dl indicating anaemia. HB concentrations of 10-10.9 g/dl, 7-9.9 g/dl, and <7 g/dl were classified as mild, moderate, and severe anaemia, respectively[5].

During pregnancy, red cell mass increases by 30% and plasma volume increases by 40 to 50%, resulting in a drop in haemoglobin concentration of 2gm/dl . This is called physiological anaemia of pregnancy. In 1998, the CDC defined anaemia in iron-supplemented pregnant women as a cutoff of 11g/dl in the first and third trimesters and 10.5g/dl in the second trimester[5] Iron deficiency anaemia during pregnancy can lead to preterm birth, low birth weight, and small-for-gestational-age babies, as well as an increased risk of postpartum haemorrhage. This explains why the prevalence of PPH is higher in India than globally[6].

METHODOLOGY

This retrospective, record-based observational study was conducted in Urban Health Training Centre with access to comprehensive medical records. The study aimed to review records from the past 2 years to assess the prevalence and impact of thyroid dysfunction and anaemia during pregnancy on foetal outcomes. The target population included pregnant women of age group 18-45 years with documented thyroid function tests (TSH, Free T3, Free T4) and haemoglobin levels, as well as complete antenatal and delivery records. Purposive sampling was employed to select all eligible singleton pregnancies with documented gestational age at testing. Records with incomplete data, multiple pregnancies, chronic diseases, or high-risk pregnancies unrelated to the study's focus were excluded.

Data were extracted from ANC (antenatal care) registers, and delivery records using a standardized data extraction form. Based on the records total 352 pregnant women were enrolled in the study.  Maternal data included age, parity, BMI, gestational age at testing, TSH levels, Free T3, Free T4, haemoglobin levels, and anaemia classification (mild, moderate, or severe). Foetal data included gestational age at delivery, birth weight, Apgar scores, neonatal thyroid function (if available), and complications such as preterm birth or intrauterine growth restriction (IUGR). Pregnancy outcomes, including the mode of delivery (normal or C-section) and maternal complications such as preeclampsia or gestational diabetes, were also recorded.

Descriptive analysis was performed to calculate the prevalence of thyroid dysfunction, anaemia, and adverse pregnancy outcomes. Inferential analysis examined the relationships between maternal thyroid or haemoglobin levels and foetal outcomes using correlation analysis. Comparative analyses were conducted to compare outcomes in women with normal versus abnormal thyroid or haemoglobin levels, using t-tests and chi-square tests. Regression models were applied to identify predictors of adverse foetal outcomes.

Ethical approval was obtained from the Institutional Ethics Committee, and strict measures were implemented to anonymize patient identifiers and ensure confidentiality. Aggregated data were used for analysis and reporting to protect privacy. The study was conducted over a 6–12 month period, with 3–6 months allocated for data extraction, 2–3 months for data cleaning and statistical analysis, and 1–2 months for report writing. The study established prevalence rates, identified correlations between maternal thyroid dysfunction or anaemia and foetal outcomes, and provided recommendations for early screening and management to improve maternal and foetal health.

RESULT

The average age of pregnant women was 26.60 ± 4.29 years (range 18-42).

Table 1:Distribution of Age ,Gravida and Parity

Table 1 presents the age distribution of the 354 pregnant women included in the study. The majority of the participants (94%) were between the ages of 20 and 35 years, with a total of 331 women falling within this age range. This indicates that most of the women in the study were in their prime reproductive years, while 15 women (4.2%) were aged 35 or older. Additionally, 6 women (1.7%) were aged 19 or younger, representing the youngest age category in the study. The gravida status of the pregnant women. Primigravida women comprised 94 women (26.7%) of the study sample, indicating a substantial proportion of women in their first pregnancy. The remaining women were multigravida, with 135 women (38.1%) having gravida G2, and 94 women (26.7%) had gravida G3. A smaller number of women, 29 women (8.24%), belong to G4 or higher gravida. The parity status, which refers to the number of live births a woman has had. The majority of the women, 161 women (45.5%), had a parity score of one (P1), meaning they had one live birth. 77 women (21.8%) had a parity of two (P2), and 60 women (16.9%) had a parity of three (P3). A smaller proportion of women, 54 women (15.3%), had a parity of four or more (P4).   

Table 2: Frequency and Percentage Distribution of Thyroid Disorders, Anaemia, and Foetal Birth Weight

Table 2 presents Frequency and Percentage Distribution of Thyroid Disorders, Anaemia, and Foetal Birth weight. The 95.45% of participants were euthyroid, while 3.13% had hypothyroidism and 1.42% had hyperthyroidism. 45.45% of participants had normal haemoglobin levels, while anaemia was observed in 54.55% of the population. Among anaemic individuals, 25.57% had mild anaemia, 26.42% had moderate anaemia, and 2.56% had severe anaemia. 84.94% of newborns had a normal birth weight, while 15.06% were classified as having low birth weight (LBW).

Table 3: Association Between foetal outcome and Thyroid dysfunction & Anaemia in mother

Among normal mothers, 140 had normal birth weight babies, while 20 had LBW babies. In anaemic mothers, 159 had normal birth weight infants, whereas 33  had LBW infants. The Chi-square value is 1.5, with a p-value of 0.2207, indicating no statistically significant association between anaemia and low birth weight (p > 0.05). Among euthyroid mothers, 287 had normal birth weight infants, while 49 had LBW infants. In hyperthyroid mothers, 4 had normal birth weight infants, and 1 had an LBW baby. Among hypothyroid mothers, 8 had normal birth weight infants, while 3 had LBW infants. The Chi-square value is 1.437, with a p-value of 0.2306, suggesting no statistically significant association between thyroid dysfunction and LBW (p > 0.05).

DISCUSSION

Pregnancy influences thyroid function and heme metabolism. Thyroid dysfunction and anaemia are both recoverable disorders. Pregnant women should therefore be screened. This record-based research of 352 pregnant women was undertaken at a UHTC affiliated with a medical college. Thyroid dysfunction has received little attention in this part of India.

The mean age of pregnant women in our study was 26.60 ± 4.29 years. The majority of them were between the ages of 20 and 35 (94%), with 4.2 percent being 35 or older and 1.7% being 19 or younger. Ninety-five ladies (26.8%) were newly pregnant. The rest were multigravida, with the majority being G2 (38.35%), followed by G3 (26.7%). The majority (45.5%) of the women had a para score of one (P1), with P2 accounting for 22.3%. In others, it was P3 or greater. Similarly, Dave et al. [20]observed that the average age of women in their study was 24.46 years. 55.08% of the women were nullipara, 31.14% were primipara, 11.47% were para 2, and 2.2% were para 3 or higher.

In our study, sixteen women (4.55%) had a history of thyroid disorders. Dave et al [20] showed that a greater number of women (4.2%) had a history of thyroid problems.

Similar to our study, Mahajan et al. [21] found that the majority of cases were delivered vaginally, followed by LSCS, and LSCS was more likely in cases with thyroid dysfunction than in euthyroid patients (OR=1.38). Other investigations, such as Taha et al [22] and Sreelatha et al [23], revealed a 30.2% and 22.9% incidence of LSCS in persons with subclinical hypothyroidism, respectively. The frequency of LSCS is higher in thyroid dysfunction because it has irreversible effects on the foetus and placenta throughout early pregnancy, increasing the risk of foetal distress in birth. Thyroid dysfunction was associated with a higher proportion of LSCS and preterm birth.

Thyroid disorder can have an impact on both maternal and foetal health outcomes. Hypothyroidism raises the risk of preeclampsia, anaemia, miscarriage, placental abruption, and preterm birth. It has an impact on foetal growth, particularly brain development, which can lead to cognitive and psychomotor issues. The average TSH levels in cases was 1.86 ± 1.37 mIU/L. Based on blood TSH levels, five (1.42%) pregnant women had hyperthyroidism, while eleven (3.13%) had hypothyroidism.  There was no significant association between foetal weight and TSH (p = 0.321). The mean TSH value for hyperthyroidism is 0.089 ± 0.097 mIU/L, while hypothyroidism is 4.62 ± 2.39 mIU/L. Mahajan et al [21] observed a similar prevalence, with 12.45% of cases having thyroid dysfunction. The prevalence of both overt hypothyroidism and subclinical hypothyroidism was 2.34% & 9.54%, respectively. The prevalence of hyperthyroidism was 0.58%. The mean TSH values in subclinical hypothyroid patients were 4.95±3.51, in overt hypothyroidism was 6.13±2.31, and in hyperthyroidism was 0.06±0.05. Mahadik et al. (24) reported that 11% of the patients showed thyroid dysfunction. The prevalence of subclinical hypothyroidism, overt hypothyroidism, and subclinical hyperthyroidism were 5.6%, 3.5%, and 1.5%, respectively. The mean TSH levels for subclinical hypothyroidism, overt hypothyroidism, and subclinical hyperthyroidism were 8.02 ± 1.25mIU/ml, 11.92 ± 5.34mIU/ml, and 0.07 ± 0.03mIU/ml. Taha et al. (22) and Singh et al. (19) showed subclinical hypothyroidism prevalence rates of 14.9% and 18%, respectively. Gupta et al. reported a prevalence of thyroid dysfunction of 10.40%, with hypothyroidism and hyperthyroidism at 6.47% and 3.93%, respectively. Other Indian research found a lower frequency of subclinical hypothyroidism Between 6-7.2% . [26-29] The prevalence fluctuates due to variations in iodine deficiency between regions.

CONCLUSION

This study highlights the prevalence and impact of thyroid dysfunction and anaemia during pregnancy on foetal outcomes. The majority of pregnant women (95.45%) were euthyroid, while 3.13% had hypothyroidism and 1.42% had hyperthyroidism. Anaemia was prevalent in 54.55% of participants, with moderate anaemia being the most common. Low birth weight (LBW) was observed in 15.06% of newborns.

Despite the presence of thyroid dysfunction and anaemia, statistical analysis did not establish a significant association between these conditions and LBW (p > 0.05). Given the potential maternal and foetal complications associated with thyroid dysfunction, routine screening and early intervention during pregnancy are recommended to improve maternal and neonatal health outcomes.

REFERENCE

1. Kumar R, Bansal R, Shergill HK, Garg P. Prevalence of thyroid dysfunction in pregnancy and its association with feto-maternal outcomes: A prospective observational study from a tertiary care institute in Northern India. Clinical Epidemiology and Global Health. 2023 Jan;19:101201
2. Mahadik K, Choudhary P, Roy PK. Study of thyroid function in pregnancy, its feto-maternal outcome; a prospective observational study. BMC Pregnancy and Childbirth. 2020 Dec;20(1).
3. S, Nadagoudar S, Devi L. A. The study of maternal and fetal outcome in pregnant women with thyroid disorders. International Journal of Reproduction, Contraception, Obstetrics and Gynecology [Internet]. 2017 Jul 26 [cited 2019 Nov 6];6(8):3507. Available from:

https://www.ijrcog.org/index.php/ijrcog/article/download/3096/2656

4. Kharate M A, Choudhari S G (July 18, 2024) Effects of Maternal Anemia Affecting Fetal Outcomes: A Narrative Review. Cureus 16(7): e64800. DOI 10.7759/cureus.64800
5. N Tejeswini, R Andallu, Hari Anupama. Effect of severity of maternal anaemia on fetal outcome. MedPulse – International Journal of Gynaecology. September 2017; 3(3): 128-131.http://medpulse.in/Gynacology/index.php
6. kothapalli suprada, Kosuri Naga Venkata Lakshmi Durga, Rao Koneru G, B RB. MATERNAL AND FETAL OUTCOME IN ANEMIA COMPLICATING PREGNANCY – A PROSPECTIVE STUDY. International Journal of Academic Medicine and Pharmacy. 2024 Jan 25;(2687-5365):607–10.
7. Altomare M, La Vignera S, Asero P, Recupero D, Condorelli R, Scollo P, et al. High prevalence of thyroid dysfunction in pregnant women. J Endocrinol Invest [Internet]. 2013 Jun [cited 2021 Oct 11]:36(6):407-11. Available from: https://pubmed.ncbi.nlm.nih.gov/23095459/
8. Stagnaro-Green A. Thyroid antibodies and miscarriage: where are we at a generation later? J Thyroid Res. 2011;2011:841949.
9. Männistö T, Vääräsmäki M, Pouta A, Hartikainen A-L, Ruokonen A, Surcel H-M, et al. Perinatal outcome of children born to mothers with thyroid dysfunction or antibodies: a prospective population-based cohort study. J Clin Endocrinol Metab. 2009 Mar;94(3):772-9.
10. Wang W, Teng W, Shan Z, Wang S, Li J, Zhu L, et al. The prevalence of thyroid disorders during early pregnancy in China: the benefits of universal screening in the first trimester of pregnancy. Eur J Endocrinol. 2011 Feb;164(2):263-8.
11. Dhanwal DK, Prasad S, Agarwal AK, Dixit V, Banerjee AK. High prevalence of subclinical hypothyroidism during first trimester of pregnancy in North India. Indian J Endocrinol Metab. 2013 Mar;17(2):281-4.
12. Singh A, Reddy MJ. Prevalence of thyroid dysfunction in pregnancy and its implications. Int J Med Sci Public Heal Online. 2015;
13. Reid S, P M, Cossich M, Crowther C. Interventions for clinicai and subclinical hypothyroidism in pregnancy. Cochrane database Syst Rev [Internet]. 2010 Jul 7 [cited 2021 Oct 12];(7). Available from: https://pubmed.ncbi.nlm.nih.gov/20614463/
14. Unnikrishnan A, Kalra S, Sahay R, Bantwal G, John M, Tewari N. Prevalence of hypothyroidism in adults: An epidemiological study in eight cities of India. Indian J Endocrinol Metab [Internet]. 2013 [cited 2021 Oct 12]:17(4):647. Available from: https://pubmed.ncbi.nlm.nih.gov/23961480/
15. Gupta P, Jain M, Verma V, Gupta NK. The Study of Prevalence and Pattern of Thyroid Disorder in Pregnant Women: A Prospective Study. Curous. 2021;13(7):1-7.
16. Brent GA. Diagnosing Thyroid Dysfunction in Pregnant Women: Is Case Finding Enough? J Clin Endocrinol Metab [Internet]. 2007 Jan 1 [cited 2021 Oct 12]:92(1):39-41. Available from https://academic.oup.com/jcem/article-abstract/92/1/39/2597924
17. Alamdari S, Azizi F, Delshad H, Sarvghadi F, Amouzegar A. Mehran L. Management of Hyperthyroidism in Pregnancy: Comparison of Recommendations of American Thyroid Association and Endocrine Society. J Thyroid Res [Internet]. 2013 [cited 2021 Oct 12]:2013. Available from: /pmc/articles/PMC3674680/
18. Sifakis S, Pharmakides G. Anemia in pregnancy. Ann NY Acad Sci. 2000:900:125-36.
19. AlexanderErik K, PearceElizabeth N, BrentGregory A, BrownRosalind S, Chen H, Dosiou C, et al. 2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum. 2017 Mar 1 [cited 2021 Oct 8]:27(3):315-89. Available from: https://www.liebertpub.com/doi/abs/10.1089/thy.2016.0457
20. Dave A, Maru L, Tripathi M. Importance of Universal screening for thyroid disorders in first trimester of pregnancy. Indian J Endocrinol Metab. 2014;18(5):735-8.
21. Mahajan K, Mahajan S. Fetal outcome in pregnancy with thyroid dysfunction: Observational study. Pravara Med Rev. 2020;12(3):37-42.
22. Taha I, Alhazmi J. Prevalence of overt and subclinical hypothyroidism among Saudi pregnant women attending tow referral hospitals in Saudi Arabia and associated maternal and fetal complications | SFEBES2011 | Society for Endocrinology BES 2011 | Endocrine Abstracts [Internet]. [cited 2021 Oct 21]. Available from: https://www.endocrine-abstracts.org/ea/0025/ea0025p312
23. Sreelatha S, Nadagoudar S, Devi L A. The study of maternal and fetal outcome in pregnant women with thyroid disorders. Int J Reprod Contraception, Obstet Gynecol. 2017;6(8):3507.
24. Mahadik K, Choudhary P, Roy PK. Study of thyroid function in pregnancy, its feto-maternal outcome; a prospective observational study. BMC Pregnancy Childbirth. 2020;20(1):1-7.
25. Paikhomba Singh K, Apabi Singh H, Kamei H, Madhuri Devi L. Prevalence of Hypothyroidism among Pregnant Women in the Sub Mountain State of Manipur. Int J Sci c Study [Internet]. 2015 [cited 2021 Oct 21]; Available from: www.ijss-sn.com
26. Pahwa S, Mangat S. Prevalence of thyroid disorders in pregnancy. Int J Reprod Contraception, Obstet Gynecol [Internet]. 2018 Aug 27 [cited 2021 Oct 21];7(9):3493-6. Available from: https://www.ijrcog.org/index.php/ijrcog/article/view/5180
27. Sri SK, Kumar Korani Ratnam P. Prevalence of thyroid disorder in pregnancy and pregnancy outcome. Int Med Journal Orig Res Artic [Internet]. 2017 [cited 2014 Med Journal Orig Redoi.org/10.26611/10041012
28. Garg R, Agrawal P, Agrawal V, Singh S. Prevalence of Thyroid Dysfunction in Pregnancy. Indian J Clin Pract. 2019;30(2).
29. Saraladevi R, Kumari N, Shreen B, Rani VU, Resident S. Prevalence of thyroid disorder in pregnancy and pregnancy outcome. Int Arch Integr Med [Internet]. 2016 [cited 2021 Oct 21];3. Available from: http://iaimjournal.com/