Volume 83, Issue 4 (July 2025)
Tehran Univ Med J 2025, 83(4): 261-268 |
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Shirvani Naghani E, Moradi L, Jahanshahi A, Rashidi H, Sedaghat A. Levothyroxine dose determination in pregnant women with and without a history of hypothyroidism and its association with thyroid peroxidase antibody (TPO) antibody levels. Tehran Univ Med J 2025; 83 (4) :261-268
URL: http://tumj.tums.ac.ir/article-1-13569-en.html
URL: http://tumj.tums.ac.ir/article-1-13569-en.html
Elham Shirvani Naghani *1 
, Leila Moradi2 , Alireza Jahanshahi2 , Homeira Rashidi2 , Alireza Sedaghat2
, Leila Moradi2 , Alireza Jahanshahi2 , Homeira Rashidi2 , Alireza Sedaghat2
1- Clinical Research Development Unit, Golestan Hospital, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
2- Department of Internal Medicine, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
2- Department of Internal Medicine, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Abstract: (492 Views)
Background: Thyroid disorders are common among young women, and hypothyroidism ranges clinically from subclinical to overt disease, potentially causing various maternal and fetal complications. Determining the appropriate levothyroxine (LT4) dose during pregnancy is crucial for maintaining maternal euthyroidism and optimising pregnancy outcomes. This study aimed to evaluate the dose requirements of LT4 in pregnant women with and without a prior history of hypothyroidism, and to investigate the association with Thyroid peroxidase antibody (TPO) levels.
Methods: This hospital- and clinic-based study was conducted from September 2022 to March 2023 among 146 pregnant women attending a private clinic or Golestan Hospital in Ahvaz, Iran. A total of 146 pregnant women diagnosed with subclinical hypothyroidism (SCH, n=62) or overt hypothyroidism (OH, n=84) were randomly selected. Participants were divided into groups based on their history of hypothyroidism and received LT4 treatment. LT4 requirements were determined according to trimester-specific TSH ranges: >10 mIU/L or 2.5-10 mIU/L in the first trimester, and 3-10 mIU/L in the second and third trimesters. Data analysis was performed using SPSS version 22, employing descriptive statistics (mean±SD, frequency, and percentage) and analytical tests, including the independent t-test and Mann-Whitney U test.
Results: Pregnant women with overt hypothyroidism showed a statistically significant difference in mean LT4 dose between those with and without a prior history of hypothyroidism (P<0.05). In contrast, no significant difference was observed in LT4 requirements among women with subclinical hypothyroidism. TPO Ab positivity was associated with higher LT4 requirements, particularly in women with overt disease. Dose adjustments were most frequent during the first trimester, with incremental increases observed in subsequent trimesters. These findings support individualized monitoring, iodine testing, adherence checks, and coordinated antenatal endocrinology care to improve maternal and neonatal outcomes.
Conclusion: Following the diagnosis of hypothyroidism in early pregnancy, LT4 dosing should be tailored according to disease severity, prior history of hypothyroidism, TPO Ab status, and study location to ensure optimal maternal and fetal outcomes.
Methods: This hospital- and clinic-based study was conducted from September 2022 to March 2023 among 146 pregnant women attending a private clinic or Golestan Hospital in Ahvaz, Iran. A total of 146 pregnant women diagnosed with subclinical hypothyroidism (SCH, n=62) or overt hypothyroidism (OH, n=84) were randomly selected. Participants were divided into groups based on their history of hypothyroidism and received LT4 treatment. LT4 requirements were determined according to trimester-specific TSH ranges: >10 mIU/L or 2.5-10 mIU/L in the first trimester, and 3-10 mIU/L in the second and third trimesters. Data analysis was performed using SPSS version 22, employing descriptive statistics (mean±SD, frequency, and percentage) and analytical tests, including the independent t-test and Mann-Whitney U test.
Results: Pregnant women with overt hypothyroidism showed a statistically significant difference in mean LT4 dose between those with and without a prior history of hypothyroidism (P<0.05). In contrast, no significant difference was observed in LT4 requirements among women with subclinical hypothyroidism. TPO Ab positivity was associated with higher LT4 requirements, particularly in women with overt disease. Dose adjustments were most frequent during the first trimester, with incremental increases observed in subsequent trimesters. These findings support individualized monitoring, iodine testing, adherence checks, and coordinated antenatal endocrinology care to improve maternal and neonatal outcomes.
Conclusion: Following the diagnosis of hypothyroidism in early pregnancy, LT4 dosing should be tailored according to disease severity, prior history of hypothyroidism, TPO Ab status, and study location to ensure optimal maternal and fetal outcomes.
Type of Study: Original Article |
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