The importance of iodine nutrition during pregnancy

AbstractObjective:To examine the importance of iodine nutrition during pregnancy.Design:Review of existing literature of iodine in pregnancy.Setting:Population surveys and metabolic studies.Subjects:Pregnant women.Results:The main changes in thyroid function associated with pregnancy are due to an increase in hormone requirements that begin in the first trimester of gestation. This increase can only be met by a proportional increase in hormone production, something that depends directly upon the availability of iodine. When dietary iodine is lacking, an adequate physiological adaptation is difficult to achieve and is progressively replaced by pathological alterations that occur in parallel with the degree and duration of iodine deprivation.Conclusions:Iodine prophylaxis should be given systematically to women during pregnancy. In most public health programmes dealing with the correction of iodine deficiency disorders, iodised salt has been used as the preferred means to deliver iodine to households. Iodised salt, however, is not the ideal means of delivering iodine in the specific instances of pregnancy, breast-feeding and complementary feeding because of the need to limit salt intake during these periods. In European countries, presently it is proposed that iodine is given to pregnant women and breast-feeding mothers by systematically administering multivitamin tablets containing iodine in order to reach the recommended dietary allowance of 250 μg iodine day-1.

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Iodised salt contribution to iodine nutrition status of pregnant and lactating women

British Journal Of Nutrition ◽

10.1017/s0007114515001543 ◽

2015 ◽

Vol 114 (1) ◽

pp. 126-133 ◽

Cited By ~ 5

Author(s):

Haihong Zhang ◽

Shengmin Lv ◽

Zhenguo Mu ◽

Weihong Li ◽

Xia Zhang ◽

...

Keyword(s):

Pregnant Women ◽

Rural Areas ◽

Salt Intake ◽

Urinary Iodine ◽

Iodine Content ◽

Nutrition Status ◽

Iodine Nutrition ◽

Lactating Women ◽

Iodised Salt ◽

The Impact

Sufficient iodine intake by pregnant and lactating women is crucial to their offspring's cognitive development. The aim of the present study was to explore the impact of iodised salt intake on the iodine status of pregnant and lactating women. Thirty towns were selected from 211 towns in the rural areas of Shijiazhuang city using probability proportionate to size sampling in this cross-sectional survey. In each selected town, forty pregnant women and forty lactating women were randomly selected to contribute urine samples to determine iodine content. The median urinary iodine content (UIC) of 1200 pregnant women in all was 146 (interquartile range (IQR) 88–239) μg/l. The median UIC in the first, second and third trimesters were 166 (IQR 92–276) μg/l, 145 (IQR 83–248) μg/l and 134 (IQR 79–221) μg/l, respectively. The median UIC in the first trimester was significantly higher than that in the third trimester (P= 0·04). The median UIC of 1200 lactating women in all was 120 (IQR 66–195) μg/l. Their median UIC in every 4-week block was higher than the WHO criteria except in weeks 25–28 and weeks 33–36 of lactation. Pregnant women's median UIC did not correlate with median salt iodine (MSI) (P= 0·402); however, there was a linear correlation between MSI and the lactating women's median UIC (P= 0·007). Iodised salt failed to provide adequate iodine to pregnant women possibly due to limited intake of iodised salt during pregnancy, though it was found to provide adequate iodine to lactating women in the rural areas of Shijiazhuang city.

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SERUM THYROXINE-BINDING GLOBULIN: DETERMINATION BY COMPETITIVE LIGAND-BINDING ASSAY IN THYROID DISEASE AND PREGNANCY

Acta Endocrinologica ◽

10.1530/acta.0.0850314 ◽

1977 ◽

Vol 85 (2) ◽

pp. 314-324 ◽

Cited By ~ 9

Author(s):

C. Mulaisho ◽

R. D. Utiger

Keyword(s):

Ligand Binding ◽

Pregnant Women ◽

Binding Assay ◽

Normal Subjects ◽

First Trimester ◽

Ligand Binding Assay ◽

Hormone Production ◽

Thyroxine Binding Globulin ◽

Serum Thyroxine ◽

Competitive Ligand

ABSTRACT Serum thyroxine-binding globulin (TBG) concentrations were measured by competitive ligand-binding assay in normal subjects and patients with a variety of abnormalities of thyroid hormone production or TBG production. The mean serum TBG concentration in 73 normal adults was 3.4 ± 0.6 mg/100 ml. No correlations with age, sex or serum thyroxine (T4) or triiodothyronine (T3) concentrations were found. Serum TBG concentrations were normal in patients with hyperthyroidism. They were significantly elevated in hypothyroid patients, and fell to normal with thyroxine treatment. In pregnant women, serum TBG concentrations were markedly increased, being 7.1 ± 1.2 (mean ± sd) mg/100 ml in women in their first trimester, 9.0 ± 1.0 mg/100 ml in the second trimester and 8.9 ± 1.6 mg/100 ml in the third trimester. There was a positive correlation between serum TBG concentration and both serum T4 and serum T3 concentrations in pregnant women. Competitive ligand-binding assay is a simple and reliable method for TBG assay and yields results similar to those of electrophoretic saturation techniques.

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Physiological adaptation in early human pregnancy: adaptation to balance maternal-fetal demands

Applied Physiology Nutrition and Metabolism ◽

10.1139/h05-003 ◽

2006 ◽

Vol 31 (1) ◽

pp. 1-11 ◽

Cited By ~ 53

Author(s):

Tracey L Weissgerber ◽

Larry A Wolfe

Keyword(s):

Fetal Growth ◽

Low Density Lipoprotein ◽

Density Lipoprotein ◽

First Trimester ◽

Physiological Adaptation ◽

Maternal Circulation ◽

Hormone Production ◽

Waste Products ◽

Maternal Adaptation ◽

Maternal Exercise

After conception, the corpus luteum, placenta, and developing embryo release hormones, growth factors, and other substances into the maternal circulation. These substances trigger a cascade of events that transform the functioning of the maternal cardiovascular, respiratory, and renal systems, which in turn alter the physicochemical determinants of [H+]. Following implantation, maternal adaptations fulfill 4 important functions that support fetal growth. Increased availability of substrates and precursors for fetal-placental metabolism and hormone production is mediated by increases in dietary intake, as well as endocrine changes that increase the availability of glucose and low-density lipoprotein (LDL) cholesterol. Transport capacity is enhanced by increases in cardiac output, facilitating the transport of substrates and precursors to the placenta, and fetal waste products to maternal organs for disposal. Maternal-fetal exchange is regulated by the placenta after 10-12 weeks gestation, but it may occur through histiotrophic mechanisms before this time. Disposal of additional waste products (heat, carbon dioxide, and metabolic byproducts) occurs through peripheral vasodilation and increases in skin blood flow, ventilation, and renal filtration. The maternal physiological adaptations described above must meet the combined demands of maternal exercise and fetal growth. More research is needed to formulate evidence-based guidelines for healthy physical activity in early pregnancy.Key words: maternal adaptation, first trimester, exercise, fetal growth and development, hormones.

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Infant neurocognitive development is independent of the use of iodised salt or iodine supplements given during pregnancy

British Journal Of Nutrition ◽

10.1017/s0007114512005880 ◽

2013 ◽

Vol 110 (5) ◽

pp. 831-839 ◽

Cited By ~ 40

Author(s):

Piedad Santiago ◽

Inés Velasco ◽

Jose Antonio Muela ◽

Baltasar Sánchez ◽

Julia Martínez ◽

...

Keyword(s):

Pregnant Women ◽

Thyroid Function ◽

Urinary Iodine ◽

Thyroid Volume ◽

First Trimester ◽

Thyroid Stimulating Hormone ◽

Neurological Development ◽

Free Triiodothyronine ◽

Iodised Salt ◽

Maternal Thyroid

The benefits of iodine supplements during pregnancy remain controversial in areas with a mild-to-moderate iodine deficiency. The aim of the present study was to determine the effect of improving iodine intakes, with iodised salt (IS) or iodine supplements, in pregnant Spanish women. A total of 131 pregnant women in their first trimester were randomly assigned to three groups: (1) IS in cooking and at the table, (2) 200 μg potassium iodide (KI)/d or (3) 300 μg KI/d. No differences were found in thyroid-stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3) or thyroid volume (TV) between the three groups. Regardless of the group in which women were included, those who had been taking IS for at least 1 year before becoming pregnant had a significantly lower TV in the third trimester (P= 0·01) and a significantly higher urinary iodine in the first (173·7 (sd81·8)v. 113·8 (sd79·6) μg/l,P= 0·001) and third trimesters (206·3 (sd91·2)v. 160·4 (sd87·7) μg/l,P= 0·03). Also, no differences were seen in TSH, FT4 or FT3. Children's neurological development was not significantly associated with the consumption of IS for at least 1 year before becoming pregnant and no differences were found according to the treatment group. In conclusion, in pregnant women with insufficient iodine intake, the intake of IS before becoming pregnant was associated with a better maternal thyroid function. The form of iodide intake was not associated with maternal thyroid function or children's neurological development.

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Inadequate iodine nutrition of pregnant women from Extremadura (Spain)

Acta Endocrinologica ◽

10.1530/eje-08-0309 ◽

2008 ◽

Vol 159 (4) ◽

pp. 439-445 ◽

Cited By ~ 12

Author(s):

Javier Sánchez-Vega ◽

Francisco Escobar del Rey ◽

Humberto Fariñas-Seijas ◽

Gabriella Morreale de Escobar

Keyword(s):

Pregnant Women ◽

Monitoring Program ◽

Urinary Iodine ◽

Iodine Concentration ◽

First Trimester ◽

Urinary Iodine Concentration ◽

Iodine Nutrition ◽

First Trimester Of Pregnancy ◽

Urine And Serum

ObjectiveTo evaluate the iodine nutrition of the pregnant women of the Spanish Autonomous Community Extremadura. There are ∼10 000 births per year in Extremadura, which historically contains areas with endemic goiter (Las Hurdes).DesignPopulation study in which a representative sample of pregnant women of the general population was analyzed, along with another sample of pregnant women from traditionally goitrogenic areas. With the collaboration of selected health centers, an additional sample of blood and urine was obtained within the primary health care pregnancy-monitoring program; these samples were sent to a single central laboratory.MethodsBiochemistry: determination of iodine and creatinine in urine, and serum concentrations of thyroxine, free thyroxine, tri-iodothyronine, TSH, thyroglobulin, and two anti-thyroid antibodies. Each parameter was measured by means of a single specific RIA.ResultsChanges between the first trimester and later stages of pregnancy of all biochemical variables studied corresponded with those described for other European areas with a comparable iodine nutrition. Using the urinary iodine concentration value as an indicator of iodine ingestion, it was found that in the first trimester of pregnancy six out of ten women from Extremadura ingested less than the currently recommended amount (250 μg I/day), and approximately three out of ten of these women ingested less than half of this amount.ConclusionsIt is imperative to implement in all Extremadura the generalized and controlled use of complements that contain 200–250 μg I/day throughout pregnancy and, if possible, before.

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Nutritional Iodine Status in Pregnant Women from Health Area IV in Asturias (Spain): Iodised Salt Is Enough

Nutrients ◽

10.3390/nu13061816 ◽

2021 ◽

Vol 13 (6) ◽

pp. 1816

Author(s):

Silvia González-Martínez ◽

María Riestra-Fernández ◽

Eduardo Martínez-Morillo ◽

Noelia Avello-Llano ◽

Elías Delgado-Álvarez ◽

...

Keyword(s):

Pregnant Women ◽

Thyroid Function ◽

Iodine Deficiency ◽

Urinary Iodine ◽

Multivariate Logistic Regression Analysis ◽

First Trimester ◽

Urinary Iodine Concentration ◽

Iodine Status ◽

Iodised Salt ◽

Health Area

Background: Iodine deficiency during pregnancy may have adverse effects on the neurodevelopment of the foetus. Recent studies of pregnant women in Asturias (Spain) indicate that nutritional iodine levels are sufficient. The objective of this study was to confirm the appropriate nutritional iodine status and to analyse the influence of the ingestion of iodine on maternal urinary iodine concentration (UIC) and thyroid function. Methods: An observational study was carried out between May and June 2017 on women in the first trimester of pregnancy from Health Area IV in Asturias. The women completed a questionnaire related to their consumption of iodine and samples were taken to analyse UIC and thyroid function. Results: Three hundred and eighteen pregnant women were involved. Of these, 51.10% used iodised salt, 48.90% consumed ≥ 2 servings of dairy products daily and 87.08% took iodine supplements. The median UIC was 171.5 μg/L (116–265 μg/L) and 60.41% of women had UIC ≥ 150 μg/L. Multivariate logistic regression analysis demonstrated that iodised salt had a protective effect on UIC < 150 μg/L (odds ratio (OR) 0.404 (0.237–0.683), p = 0.001), but not iodine supplements (OR 0.512 (0.240–1.085), p = 0.080). The average level of thyroid stimulating hormone (TSH) was 2.26 ± 0.94 mIU/L; 68.40% of pregnant women taking iodine supplements had TSH < 2.5 mIU/L compared to 30.00% of those who were not taking supplements (p = 0.031). Conclusions: The pregnant women in our health area are maintaining appropriate nutritional iodine levels. The consumption of iodised salt protects against iodine deficiency; thus, iodine supplements should be taken on an individualised basis.

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Optimisation of tactics of conducting pregnancy and labours at women after auxiliary reproductive technologies

HEALTH OF WOMAN ◽

10.15574/hw.2016.111.160 ◽

2016 ◽

pp. 160-164

Author(s):

D.N. Maslo ◽

Keyword(s):

Pregnant Women ◽

Resistance Index ◽

First Trimester ◽

Reproductive Technologies ◽

Premature Delivery ◽

Control Group ◽

Uterine Arteries ◽

Placental Dysfunction ◽

Placental Blood ◽

Two Stages

The objective: frequency decrease perinatal pathologies at women after ART on the basis of studying clinical-ehografical, endocrinological, biochemical, dopplerometrical, cardiotokografical and morphological researches, and also improvement of algorithm of diagnostic and treatment-and-prophylactic actions. Patients and methods. The work basis is made spent by us from 2012 on 2015 by complex inspection of 300 pregnant women from which 250 were after ART and 50 – firstlabours which pragnency without ART, and also their newborns. For the decision of an object in view of research spent to two stages. At 1 stage spent prosperctive research which included 150 pregnant women: з them 100 women pregnancy at which has come out ART (1 group) and 50 healthy women (control group). At 2 stage spent prospective randomization in which result of patients after ART have divided on two equal groups by therapy principle: 2 basic group - 75 pregnant women after ART at which used the algorithm improved by us; 3 group of comparison - 75 pregnant women after ART which have been spent on the standard treatment-and-prophylactic actions. Results. The results suggest that women after using ART is a high frequency of reproductive losses in the first trimester (10.0%), 3.0% of spontaneous abortion from 16 to 22 weeks, and 3.0% "early" premature delivery (22 to 28 weeks of pregnancy). The frequency of violations of the functional state of placenta in women after using IVF is 63.0%, which is the main cause of high levels of perinatal losses (40.0 ‰), and delivery by cesarean section (96.0%). Placental dysfunction in women after using ART characterized by retrohorialnyh hematoma (21.0%); size mismatch fruit (30.0%) and hypertonicity of the uterus (73.0%) against changes in fruit-placental blood flow - increased resistance index in umbilical artery and increased vascular resistance in the uterine arteries. Endocrinological and biochemical changes in placental dysfunction in women after using IVF starting from 28 weeks of pregnancy and are in significant reduction in progesterone, placental b1-microglobulin, B2-microglobulin of fertility and trophic в-glycoprotein. Conclusion. The received results: use of the algorithm of diagnostic and treatment-and-prophylactic actions improved by us allows to lower frequency of spontaneous interruption of pregnancy till 22 weeks – from 13.0% to 5.7%; «early» premature birth – from 3.0% to 1.0%; placentary dysfunction from 63.0% to 40.6%; cesarean sections – from 96.0% to 56.5%, and also perinatal losses – from 40.0‰ to 16.2‰. Key words: pregnancy, childbirth, auxiliary reproductive technologies.

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