The regulation of thyroid function during normal pregnancy: importance of the iodine nutrition status

This study aimed to observe the relationship between iodine nutrition status (dietary iodine intake and estimated iodine intake based on urinary iodine concentration (UIC)) and thyroid disease-related hormones. This study involved 6090 subjects >19 years old with valid UIC, assessed between 2013 and 2015 by the Korean National Health and Nutrition Examination Survey, using a stratified, multistage, clustered probability-sampling design. The estimated iodine intake in participants was measured using UIC and urine creatinine. To examine the effect of iodine intake on thyroid disease, the iodine intake was divided into Korean Dietary Reference Intakes groups, and logistic regression analysis was performed via the surveylogistic procedure to obtain odds ratios (ORs) and 95% confidence intervals (CIs). The estimated iodine intake showed a significant positive correlation with dietary iodine intake (r = 0.021, p < 0.001), UIC (r = 0.918, p < 0.001), and thyroid-stimulating hormone (TSH) (r = 0.043, p < 0.001), but a significant negative correlation with free thyroxine (FT4) (r = −0.037, p < 0.001). Additionally, as the estimated iodine intake increased, age, TSH, and UIC increased, but FT4 decreased (p for trend < 0.0001). The risk of thyroid disease was higher in the “≥tolerable upper intake level (UL ≥ 2400 µg/day)” group than in the “<estimated average requirement (EAR < 150 µg/day)” group in females (OR: 2.418; 95% CI: 1.010–5.787). Also, as iodine intake increased, the risk of thyroid disease increased (p for trend < 0.038).

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Test of thyroid function in normal pregnancy using radioactive iodine

American Journal of Obstetrics and Gynecology ◽

10.1016/0002-9378(58)90419-8 ◽

1958 ◽

Vol 75 (2) ◽

pp. 461

Author(s):

Francis B. O'Brien

Keyword(s):

Thyroid Function ◽

Radioactive Iodine ◽

Normal Pregnancy

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Iodine Nutrition Status in Pregnant Women in Mexico

Thyroid ◽

10.1089/thy.2011.0197 ◽

2011 ◽

Vol 21 (12) ◽

pp. 1367-1371 ◽

Cited By ~ 11

Author(s):

Pablo García-Solís ◽

Juan Carlos Solís-S ◽

Ana Cristina García-Gaytán ◽

Vanessa Amaranta Reyes-Mendoza ◽

Ludivina Robles-Osorio ◽

...

Keyword(s):

Pregnant Women ◽

Nutrition Status ◽

Iodine Nutrition

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Thyroid dysfunction in preeclampsia and related fetomaternal outcomes

International Journal of Reproduction Contraception Obstetrics and Gynecology ◽

10.18203/2320-1770.ijrcog20191944 ◽

2019 ◽

Vol 8 (5) ◽

pp. 1928

Author(s):

Puja Banik ◽

R. K. Praneshwari Devi ◽

Aheibam Bidya ◽

Akoijam Tamphasana ◽

M. Agalya ◽

...

Keyword(s):

Thyroid Function ◽

Thyroid Dysfunction ◽

Birth Asphyxia ◽

Normal Pregnancy ◽

Thyroid Stimulating Hormone ◽

Severe Preeclampsia ◽

Intrauterine Fetal Death ◽

Overt Hypothyroidism ◽

Thyroid Function Tests ◽

Cross Sectional

Background: Changes in thyroid function in normal pregnancy are well-documented but in complicated pregnancy like preeclampsia, very little is known. Studies have shown evidences of hypothyroidism in preeclampsia necessitating thyroid function tests to be done in preeclampsia. The study was done to analyze the fetomaternal outcome of preeclampsia with coexisting thyroid dysfunction.Methods: A cross-sectional analytical study was done over 18 months on 95 preeclamptic patients admitted at the antenatal ward and fetomaternal outcomes were analyzed according to thyroid status.Results: Out of 95 patients with preeclampsia, 42 (44.2%) had thyroid dysfunction. Among these 42 patients, 37 (38.9%) patients had subclinical hypothyroidism, 4 (4.2%) had overt hypothyroidism and 1 (1%) had hyperthyroidism. Severe preeclampsia was seen in 64.3% of the patients with thyroid dysfunction compared with 39.6% in euthyroid patients. The mean thyroid stimulating hormone (TSH) level was significantly higher and means free thyroxine (fT4) level was significantly lower in severe preeclampsia compared with non-severe preeclampsia. Complications like abruption, intrauterine fetal death (IUD), intrauterine growth restriction (IUGR), oligohydramnios, preterm deliveries, postpartum hemorrhage (PPH), low birth weight babies, birth asphyxia in babies and subsequent neonatal intensive care unit (NICU) admissions were significantly higher (p <0.05) in the preeclampsia patients with thyroid dysfunction in comparison with euthyroid ones.Conclusions: Hypothyroidism may be a modifiable risk factor for preeclampsia. Thyroid screening early in pregnancy may be helpful in predicting the occurrence of preeclampsia and timely thyroid hormone administration can reduce the maternal and perinatal morbidity and mortality associated with preeclampsia.

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Distribution of thyroid peroxidase positivity and its effects on thyroid function in normal pregnant women during 1st trimester in Dhaka city

Update Dental College Journal ◽

10.3329/updcj.v4i1.21160 ◽

2014 ◽

Vol 4 (1) ◽

pp. 15-20

Author(s):

Ohida Sultanaa ◽

Nasim Jahan ◽

Nayma Sultana ◽

Farzana Mahmudad ◽

Tazdik G Chowdhurye

Keyword(s):

Pregnant Women ◽

Thyroid Function ◽

First Trimester ◽

Normal Pregnancy ◽

Control Group ◽

Thyroid Peroxidase ◽

Study Group ◽

Cross Sectional ◽

Total Study Population ◽

Group B

Objective: To measure the distribution of TPO-Ab positivity and to observe the effect of thyroid peroxidase positivity on thyroid function during first trimester in normal pregnancy. Method: A cross sectional among 120 subjects were taken in this study and divided into control and study groups. Control group (Group A) consisted of 60 healthy non pregnant women age ranged between 20 to 35 years. Study group (Group B) consisted of 60 normal pregnant women of same age range. Group B was further subdivided into group B1 and group B2according to the level of TPO-Ab. Group B1 consisted of TPO-Ab positive pregnant women and group B2 consisted of TPO- Ab negative pregnant women. Control group was selected from personal contacts and study group from Out Patient Department (OPD) of Obstetrics and Gynecology of Sir Salimullah Medical College and Mitford Hospital. For assessment of thyroid function, serum free thyroxine (FT4), thyroid stimulating hormone (TSH) were measured. Serum FT4, TSH were measured by Enzyme link immunosorbant (ELISA) method. Again, serum TPO-Ab of total study population and hCG of all the pregnant women were measured. Serum TPO-Ab by Micro particle Enzyme Immunoassay (MEIA) method and hCG was estimated by ELISA. Statistical analysis was done by SPSS version 17. Results: In this study, serum FT4 and was significantly (P<0.001) higher and TSH level was significantly (P<0.001) lower in normal pregnant women during 1st trimester in comparison to those of non pregnant women. Again, 18% of pregnant women showed TPO-Ab positivity. However, serum FT4 level was significantly (P<0.001) lower whereas, TSH level was significantly (p<0.001) higher in TPO-Ab positive pregnant women in comparison to those of TPO-Ab negative pregnant women. Conclusion: TPO-Ab positivity increases during 1st trimester of normal pregnancy which decreases the hyper functional state of thyroid hormones. So, thyroid screening should be done routinely during pregnancy. DOI: http://dx.doi.org/10.3329/updcj.v4i1.21160 Update Dent. Coll. j: 2014; 4 (1): 15-20

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