IODINE AND PREGNANCY D r - PowerPoint Presentation

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IODINE AND PREGNANCY

D

r

Sedigheh

Hantoushzadeh

Why iodine is

necessory

Iodine is an essential element for human survival since it is essential for making thyroid hormones.

Iodine deficiency disorders (IDD) have been recognized as a major public health problem worldwide

According to the reports of World Health Organization (WHO) and United Nations Children’s Fund (UNICEF), more than 30% of school-aged children (260 million) suffer from insufficient iodine intake

The term "iodine deficiency disorders" (

IDD)

refers to all of the consequences of iodine deficiency, which depend on its severity and the age of the affected subject

Iodine is an essential component of thyroxine (T4) and tri iodothyronine (T3), and it must be provided in the diet. Inadequate iodine intake leads to inadequate thyroid hormone production, and all the consequences of iodine deficiency stem from the associated hypothyroidism.

Iodine is particularly important during preconception and the first 16 weeks of pregnancy, when the developing fetus is entirely dependent on the mother for its supply of iodine and the thyroid hormone.

This topic will review the consequences of iodine deficiency, its geographical distribution, diagnostic measures, prophylaxis, and treatment.

RESOURSE

Iodine can be obtained by consumption of foods that naturally contain it (

fish, seafood, kelp, some drinking water, and vegetables grown in iodine-sufficient soil

) or to which it is added

(iodized table salt or foods enriched with iodine).

Cow's milk

is a source of iodine owing to iodine in cattle feed and the use of iodophor udder cleansers in the dairy industry.

Sea salt naturally contains only a small amount of iodine.

Dietary iodine is absorbed as iodide and rapidly distributed in the extracellular fluid, which also contains iodide released from the thyroid and by extrathyroidal deiodination of the iodothyronines. Iodide leaves this pool by transport into the thyroid and excretion into the urine.

Iodine Homeostasis in Pregnancy

Physiologic Changes in Pregnancy

Pregnancy induces several major changes to thyroid physiology.

Effects of Iodine Deficiency

Mild-to-Moderate Iodine Deficiency

The effects of mild-to-moderate iodine deficiency are less well understood than those of severe iodine deficiency. 

Minor neuropsychological defects

A small study found a significantly greater prevalence of attention deficit hyperactivity disorder (ADHD) 

The World Health Organization

(WHO)

recommends a daily intake of

90 mcg of iodine for infants and

children up to 5 years

120 mcg for children 6 to 12 years

150 mcg for children ≥12 years and adults

250 mcg during pregnancy and lactation

the National Academy of Medicine

recommended minimum daily intake of iodine

90 mcg for children 1 to 8 years old

120 mcg for children 9 to 13 years old

150 mcg for older adolescents and nonpregnant adults

220 mcg for pregnant women

290 mcg for lactating women

ASSESSMENT OF IODINE NUTRITION

In practice, urinary iodine is most often used to determine iodine nutrition at the population level.

The urinary iodine concentration indicates current iodine nutrition,

while thyroid size and the serum thyroglobulin concentration reflect iodine nutrition over a period of months or years.

Urinary iodine excretion

Mild iodine deficiency is defined as a median urinary iodine concentration of 50 to 99 mcg/L,

moderate deficiency as 20 to 49 mcg/L,

and severe deficiency as <20 mcg/L

Thyroid size

—

Thyroid size is a sensitive marker for iodine deficiency because goiter, although not the most severe consequence of iodine deficiency, is the most clinically evident.

Assessment by palpation is too crude to be anything more than qualitative except in severe deficiency, but ultrasonography is precise, quantifiable, and easily performed.

PROPHYLAXIS AND TREATMENT

Community

—

Iodine deficiency is a global public health problem and, in combating it, emphasis should be placed on diagnosis and correction at the level of the community rather than the individual.

Achieving sufficient iodine nutrition in the population would eliminate the need for specific supplementation during pregnancy and lactation.

During pregnancy and lactation

Iodine repletion in the doses used for iodization of salt and in prenatal supplements has few adverse effects

Iodine administration may result in clinically significant hyperthyroidism in patients with endemic goiter or in patients with nodular goiters containing autonomously functioning tissue.

In contrast, iodine administration may induce or exacerbate hypothyroidism in patients with underlying autoimmune thyroiditis .

Maternal and neonatal outcomes and determinants of iodine deficiency in third trimester of pregnancy in an iodine

sufficient area

Soraya Saleh

Gargari

, 

Reyhaneh

Fateh

, 

Mina

Bakhshali-bakhtiari

, 

Masoumeh Saleh

, 

Masoumeh

Mirzamoradi

 & 

Mahmood

Bakhtiyari

BMC Pregnancy and Childbirth volume 20, Article number: 174 (2020)

 Iodine deficiency in pregnant women can be improved by appreciate planning for pregnancy, proper inter-pregnancy time interval (> 12 months to < 5 years), appropriate nutrition during pregnancy. Besides, controlling maternal urinary iodine concentrations is important to prevent neonatal complications such as preterm delivery and NICU admission.

Review of Iodine Nutrition in Iranian Population in the Past Quarter of Century

Hossein Delshad

1

 and 

Fereidoun

Azizi

1,*2017

The success of iodine deficiency control program depends on well designed programmatic steps and mandatory iodized salt consumption in certain situations. The iodine intake of school children is sufficient, however,

Iranian pregnant women are suffering from moderate iodine deficiency and need iodine supplementation

.

Appropriate Iodine Nutrition in Iran: 20 Years of Success

Hossein

Delshad

2010

Iodine Deficiency Disorders in the South of Iran during 1989-2012

: A Surveillance System Report Alireza Mirahmadizadeh1 , Elham Kavoosi2, Marzieh Vakili2,

Razieh

Shenavar2, Mohsen

Moghadami

Evaluation of Iodine Nutritional Status in Tehran, Iran: Iodine Deficiency Within Iodine Sufficiency

Pantea

Nazeri

Parvin

Mirmiran

Yadollah

Mehrabi

Mehdi

Hedayati

Hossein

Delshad

and 

Fereidoun

Azizi

Mild iodine deficiency has recurred in

Tehranians

. The results emphasize the need for continuous monitoring in all regions, even in a country with iodine sufficiency.