Treatment of primary hypothyroidism during pregnancy: Is there an increase in thyroxine dose requirement in pregnancy?

Chopra, Inder J.; Baber, Khansa

doi:10.1053/meta.2003.50019

Cited by 43 publications

(26 citation statements)

References 19 publications

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“…Some studies demonstrate that 85% of hypothyroid women needed an increase in LT 4 supplementation during pregnancy (33,34). However, this increased requirement may only be experienced by a subset of hypothyroid patients (35). Once time-specific reference intervals are established, the LC/MS/MS can be used to structure these adjustments individually to support the rate of increase and not just absolute values.…”

Section: Discussionmentioning

confidence: 99%

Trimester-Specific Changes in Maternal Thyroid Hormone, Thyrotropin, and Thyroglobulin Concentrations During Gestation: Trends and Associations Across Trimesters in Iodine Sufficiency

Soldin

Tractenberg²,

Hollowell³

et al. 2004

Thyroid

220

130

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Objectives-To describe the interrelationships of thyroid functions based on trimester-specific concentrations in healthy, iodine-sufficient pregnant women across trimesters, and postpartum.Methods-Circulating total 3,5,3′-triidothyronine (T 3 ) and thyroxine (T 4 ) concentrations were determined simultaneously using liquid chromatography tandem mass-spectrometry (LC/MS/MS). Free thyroxine (FT 4 ), thyroid-stimulating hormone (TSH), and thyroglobulin (Tg) were measured using immunoassay techniques. Linear mixed effects models and correlations were calculated to determine trends and associations, respectively, in concentrations.Results and conclusions-Trimester-specific T 3 , FT 4 , TSH, and Tg concentrations were significantly different between the first and third trimesters (all p < 0.05); second and third trimester values were not significantly different for FT 4 , TSH, and Tg (all p > 0.25) although T 3 was significantly higher in the third, relative to the second trimester. T 4 was not significantly different at any trimester (all p > 0.80). With two exceptions, analyte concentrations tended not to be correlated at each trimester and at 1-year postpartum. One exception was that T 3 and T 4 tended to be associated (all p < 0.05) at all time points except the third trimester (ρ = 0.239, p > 0.05). NIH Public Access

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Section: Discussionmentioning

confidence: 99%

Trimester-Specific Changes in Maternal Thyroid Hormone, Thyrotropin, and Thyroglobulin Concentrations During Gestation: Trends and Associations Across Trimesters in Iodine Sufficiency

Soldin

Tractenberg²,

Hollowell³

et al. 2004

Thyroid

220

130

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“…44 Possible LT 4 interactions with coexisting diseases, such as gastritis, 66 or medications, such as iron supplements, calcium, vitamins, or omeprazole, may reduce LT 4 absorption. 67 In those cases, it is best to advise a 4-hour delay between the medications and LT 4 .…”

Section: Managementmentioning

confidence: 99%

Autoimmune Thyroid Disease in Pregnancy: A Review

Galofré

Davies

2009

Journal of Women's Health

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The maternal physiological changes that occur in normal pregnancy induce complex endocrine and immune responses. During a normal pregnancy, thyroid gland volume may enlarge, and thyroid hormone production increases. Hence, the interpretation of thyroid function during gestation needs to be adjusted according to pregnancy-specific ranges. The elevated prevalence of gestation-related thyroid disorders (10%-15%) and the important repercussions for both mother and fetus reported in multiple studies throughout the world denote, in our opinion, the necessity for routine thyroid function screening both before and during pregnancy. Once thyroid dysfunction is suspected or confirmed, management of the thyroid disorder necessitates regular monitoring in order to ensure a successful outcome. The aim of treating hyperthyroidism in pregnancy with antithyroid drugs is to maintain serum thyroxine (T 4 ) in the upper normal range of the assay used with the lowest possible dose of drug, whereas in hypothyroidism, the goal is to return serum thyroid-stimulating hormone (TSH) to the range between 0.5 and 2.5 mU=L.

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“…One such factor is the amount of LT 4 absorbed in the gastrointestinal tract, which is altered by various medical disorders (10)(11)(12), several medications (13)(14)(15)(16), and food and drink (17)(18)(19). The timing of LT 4 administration also has an impact on its absorption (18,(20)(21)(22).…”

Section: Introductionmentioning

confidence: 99%

Levothyroxine Replacement Doses Are Affected by Gender and Weight, But Not Age

Devdhar

Drooger

Pehlivanova

et al. 2011

Thyroid

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Background: Body weight (BW) and age have been shown to affect the dose of levothyroxine (LT 4 ) that results in normalization of serum thyroid-stimulating hormone (TSH) in hypothyroid patients. Our objective was to determine whether gender, menstrual status, and ideal BW (IBW) also affect the LT 4 dose required to achieve a serum TSH within the normal range. Methods: We retrospectively reviewed the charts of patients being treated for primary hypothyroidism who had TSH values within a normal range. We selected patients aged 18-85 years who were taking LT 4 without any confounding medications, and who had no serious chronic conditions. Their LT 4 doses, referred to here as LT 4 dose requirements, based on both BW and IBW were documented. The relationship between gender, menstrual status, age, serum TSH concentrations, and the degree of overweight on LT 4 dose requirements were determined using multivariate analyses. Results: Women were significantly more overweight than men (ratio of BW/IBW was 1.35 for women vs. 1.17 for men, p < 0.0001). LT 4 requirements based on BW did not differ by gender when age was included in the model. However, when degree of overweight was also included, men required lower LT 4 doses than both premenopausal women (1.34 mg/kg vs. 1.51 mg/kg, p ¼ 0.038) and menopausal women (1.34 mg/kg vs. 1.49 mg/ kg, p ¼ 0.023). When examining IBW using a model incorporating age, men also required lower LT 4 doses than both premenopausal women (1.64 mg/kg vs. 1.92 mg/kg, p ¼ 0.0033) and menopausal women (1.64 mg/kg vs. 1.90 mg/kg, p ¼ 0.0024). Serum TSH concentrations were not significantly different in any of the gender groups. There was no relationship between serum TSH and either age or BW. The initial serum TSH concentration was by design with the normal range, but the concentration within that range was not a significant predictor of the LT 4 replacement dose in any of the models. Conclusion: In contrast to previous studies suggesting that age affects LT 4 replacement requirements, we found that age-based differences in doses are secondary to differences in BW and gender. In addition, in contrast to prior studies showing that lean body mass, but not gender, affected LT 4 dose, we instead found a significant impact of gender. Gender-based differences in dose requirement only became apparent either when IBW was used to correct for the dose or when degree of overweight was included in the model. Gender differences in LT 4 dose requirement exist, but are masked unless gender-based differences in degree of overweight are also considered.

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Treatment of primary hypothyroidism during pregnancy: Is there an increase in thyroxine dose requirement in pregnancy?

Cited by 43 publications

References 19 publications

Trimester-Specific Changes in Maternal Thyroid Hormone, Thyrotropin, and Thyroglobulin Concentrations During Gestation: Trends and Associations Across Trimesters in Iodine Sufficiency

Trimester-Specific Changes in Maternal Thyroid Hormone, Thyrotropin, and Thyroglobulin Concentrations During Gestation: Trends and Associations Across Trimesters in Iodine Sufficiency

Autoimmune Thyroid Disease in Pregnancy: A Review

Levothyroxine Replacement Doses Are Affected by Gender and Weight, But Not Age

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