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العنوان
Assessment Of Normal Range Of Thyroid Functions In Healthy Egyptian Pregnant Women /
المؤلف
Hegab,Ahmed Magdy El Morsy.
هيئة الاعداد
باحث / Ahmed Magdy El Morsy Hegab
مشرف / Nermin Ahmed Sheriba
مشرف / Nesma Ali Ibrahim
مشرف / Nagwa Roshdy Mohamed
تاريخ النشر
2017
عدد الصفحات
157p.;
اللغة
الإنجليزية
الدرجة
ماجستير
التخصص
علم الغدد الصماء والسكري والأيض
تاريخ الإجازة
1/1/2017
مكان الإجازة
جامعة عين شمس - كلية الطب - امراض الغدد الصماء والأيض
الفهرس
Only 14 pages are availabe for public view

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from 157

Abstract

Modern studies describe thyroid disease as the second most frequent endocrine disorder that can affect women in their reproductive age. When thyroid disease remains untreated in a pregnant woman some disorders can appear (Moncayo, et al., 2015).
Aim of our work is Assessment of normal range of thyroid functions (TSH, free T3 and free T4) in healthy pregnant Egyptian women with negative Anti-Tpo antibodies in the three trimesters. The lack of standardizations of free thyroid hormone measurements makes it difficult to apply a universally accepted standard reference value for it. Thus, it was necessary to develop our own normal values.
This study was done in the Obstetric clinic at Ain-Shams University Hospital at 2016, it is a randomized cross sectional study designed to analyze data from 360 apparently healthy pregnant women in Egypt, which were divided into 3 groups according to gestational age.
380 pregnant women were invited to participate in the study. We excluded 18 women who were positive to Anti-Tpo Antibodies (5%) and 2 women who were overt hypothyroidism (0.5%). A total of 360 women with singleton pregnancies were included in the final study population.
The mean + SD maternal age of our women was 25.18 ± 5.36 years with range between 18 -39 years old. The mean + SD gestational age at which laboratory and BMI determinations were performed was 20.5 + 9.9 weeks with range between 6 -39 weeks. The mean + SD BMI of our pregnant women was 24.7 + 3.86 kg/m2 with range between 16.3 -44.8 kg/m2. The socioeconomic status of our pregnant patients was uniformly intermediate.
According to laboratory data, the mean + SD TSH of our women was 1.61 + 1.13 μIU/ml with range between 0.01 -3.5 μIU/ml. The mean + SD Free T3 of our women was 2.97 + 0.63 Pg/ml with range between 2.14 -4.05 Pg/ml. The mean + SD Free T4 of our women was 1.06 + 0.22 ng/dl with range between 0.7 -1.51 Pg/ml.
Subclinical hyperthyroidism (TSH < 0.5) was diagnosed in 5 patients (1.1%); Subclinical hypothyroidism (TSH > 2.5) was diagnosed in 17 patients (%4.7). TSH was between 0.5 -1 μIU/ml in 31 (8.6%) women, 1-1.5 μIU/ml in 100 (28%) women, 1.5 -2 μIU/ml in 175 (48.6%) women and 2 - 2.5 μIU/ml in 32 (9.1%) women TSH value increased with advancing pregnancy from 1.43 ± 1.16 μIU/mL in the first trimester to 1.78 ± 1.19 μIU/mL in the third trimester, and the difference was statistically significant. The free T4 level decreased from 1.16 ± 0.23 ng/dL in the first trimester to 0.98 ± 0.17 ng/dL in the third trimester. The free T3 level decreased from 3.18 ± 0.52 ng/dL in the first trimester to 2.79 ± 0.38 ng/dL in the third trimester.
There are many trimester specific reference ranges studies. However, the comparison between the studies is not an easy task mostly due to using different laboratory methods for estimation of thyroid hormones, and also due to different inclusion and exclusion criteria (Almomin, et al., 2016).
The strengths of our study include its large sample size, wide range of maternal age between 18 -39 years old, wide range of gestational age 6 -39 weeks, the exclusion of women with thyroid autoimmunity in determining thyroid function test reference intervals and equal number of participants in each trimester.
Maternal overt hypothyroidism, subclinical hypothyroidism, and hypothyroxinemia are associated with adverse outcomes in pregnancy, including miscarriage, pregnancy-induced hypertension, preterm delivery, placental abruption, and impaired neuropsychological development of children (Wang, et al., 2011).
Uncontrolled thyrotoxicosis during pregnancy was associated with miscarriage, pregnancy-induced hypertension, premature birth, low birth weight, fetal growth restriction, still birth, thyroid crisis, and congestive heart failure. Therefore, early diagnosis of thyroid dysfunction during pregnancy and onset of rational therapy can alleviate the adverse outcomes of pregnancy (Mannisto, et al., 2013).
The most appropriate screening test for thyroid dysfunction in early pregnancy is still uncertain. Most would advocate using TSH as the initial screening test, because TSH is a more sensitive marker of thyroid status than FT4 and it reflects the physiologic log/linear relationship of TSH to FT4 (Wang, et al., 2011).
The demonstration that low and even undetectable TSH in the presence of normal thyroid hormone concentrations in the first trimester of gestation is not associated with negative outcomes, and may even be a protective factor against some outcomes, supports the physiological nature of this finding. Therefore, treatment of pregnant women with anti-thyroid drugs should only be considered when undetectable TSH is accompanied by elevated levels of T4 and/or T3 and in the presence of underlying thyroid disease (most frequently Graves’ disease) ( Rosario, et al., 2015).
The upper limit of normal for TSH is the most important parameter in clinical practice for both adjustment of the L-T4 dose in patients receiving hormone replacement therapy and the indication of this therapy ( Rosario, et al., 2015).
In contrast to low TSH, which alone is not an indication for treatment, in pregnant women with elevated TSH L-T4 replacement therapy is indicated even in the presence of normal T4 concentrations and in the absence of TPOAb. Furthermore, normal TSH weakens the indication for hormone replacement therapy even in the presence of hypothyroxinemia or circulating TPOAb (Rosario, et al., 2015).