2. Research Institute For Endocrine Sciences
Iodine nutrition
during pregnancy
H. Delshad M.D
Endocrinologist
Research Institute For Endocrine Sciences

3. What is Iodine ?
● Iodine is a chemical element (as are Oxygen,Hydrogen,Iron) ● Iodine is an essential trace element for the human ● Iodine is an essential part of the chemical structure of thyroid hormones
Total quantity present in body is (15-20 mg) Mostly in thyroid gland

4. Discovery of Iodine ● Bernard Courtois discovered Iodine in 1811
● Like most other discoveries, the discovery of Iodine was a fortuitous
accident. 
● While most scientists discovered something when trying to help people
to save their lives, Courtois discovered Iodine when he was trying to kill people.

5. TSH T3 T4
Iodine
Thyroid Hormone Synthesis

6. Iodine nutrition and thyroid function
Iodine is an essential component of thyroid hormone.
In turn, thyroid hormone is critical for neurological development both in utero and in early life.

7. Thyroid hormone Brain Maturation Stimulate: Genes for myelin
Neurotrophins and their receptors
Cytoskletone components
Transcription factors
Matrix proteins
Adhesion molecules
Intracellular signaling molecules
Mitocondrail gens
Cerebellar gens

8. Thyroid hormone Mediates growth Brown Fat Thermogenesis Body growth
Cell differentiation
Bone maturation
Chondrocyte differentiation
Brown Fat Thermogenesis
Non shivering thermogenesis to keep desired body temperature

9. Importance of iodine in brain development
50,000 brain cells produced/second in developing fetal brain
100 billion brain cells in adult
One million billion connections between these brain cells: Determine IQ

10. Importance of iodine in brain development
● % of human brain development occurs between 3rd month of pregnancy & 3rd year of life
● Maternal T4 essential for first 24 weeks
● Foetal T4 starts at 24 weeks

12. Recommended daily intake of iodine
Preschool children
90 g
Schoolchildren (6-12 y)
120 g
Adult (>12 y)
150 g
Pregnant & Lactating women
250 g

13. Iodine Requirement (g/day)
During pregnancy
Basal
40-50 % increased T4 requirements
Transfer of T4 and I from mother to fetus
Increased renal clearance of I ?
During lactation
Basal
L milk/day x gI/L
Delange: Int.J. Endocrinol. Metab. 2: 1, 2004

14. Physiologic Changes in Thyroid Function During Pregnancy
Thyroid binding globulin (TBG) increases due to reduced hepatic clearance and estrogenic stimulation of TBG synthesis
The test results that change in pregnancy are influenced by changes in TBG concentration
Plasma iodide levels decrease due to fetal iodide use and increased maternal clearance -> leads to notable increase in gland size in 15% of women (without abnormal TFTs)

16. The spectrum of IDD Fetus Neonate Child & adolescent Adult Abortions
4/24/2018
The spectrum of IDD
Fetus
Abortions
Stillbirths
Congenital anomalies
Increased perinatal mortality
Neurologic creatinism
Psychomotor defects
Neonate
Neonatal goiter
Neonatal hypothyroidims
Child & adolescent
Goitrous juvenile hypothyroidism
Impaired mental function
Retarded physical development
Adult
Goiter with its complications
Hypothyroidism

17. The adverse effects of iodine deficiency in populations (decreased IQ, goiter, hypothyroidism, and hyper-thyroidism) are easily corrected with salt iodisation.
Adequate iodine nutrition in the general population is shown by a median urinary iodine concentration for school-age children
(aged 6–12 years) of 100–299 μg/L
Adequate iodine nutrition in pregnant women is shown by a median urinary iodine concentration between 150 and 499 μg/L

18. Iodine nutrition and thyroid function
Mild –moderate iodine deficiency has re-emerged in countries previously believed to be iodine sufficient.
Lately, there has been increasing concern that even mild-to-moderate iodine deficiency has adverse clinical outcomes.
Iodine nutrition during pregnancy has become an important public health concern

19. Author Country % UIC < 150 µg/L Katz PM 2013 Canada Toronto 142 221
pregnant women
( n )
Median UIC µg/L
( IQR )
% UIC < 150 µg/L
Katz PM
2013
Canada
Toronto
142
221
( 142 – 397 )
29.6
Lindorfer H
2015
Austria
Viena
246 87
86.2
Granfors M
Sweden
459 98
( 57 – 148)
100
Fuse Y
2011
Japan
934
219
16.1
Bath SC UK
230
56.8
2014
South East UK
85.3 86
Knight BA
2016
South West UK
308 88
( 54.3 – 157.5) 73
Kirkegeard
Denmark
240
Iodine user : 118
( 79 – 196 )
Non-users: 82
( 41 – 122)

20. Author Country % UIC < 150 µg/L Kasap B 2016 Turkey 135 222
pregnant women
( n )
Median UIC µg/L
( IQR )
% UIC < 150 µg/L
Kasap B
2016
Turkey
135
222
( 141 – 397 )
28.1
Ferreiya SM
2014
Brazil
191
137.7
(132.9 – ) 92
Bilek R
Czech
Republic
532 82
71.2
De Zoysa E
Sri Lanka
425
105
(67 – 153) 98
Konrad I
2015
Latvia
696
69.4
(53.9 – 92.6 )
100
Raverot V
2012
French
Lyon
228 81
( 8 – 832 ) 77
Choyy
Korea
344
427.3 -

21. پايـش ملی دريافت يـد و عملکردغده تيروئيد زنان باردار کشور در سال 1392
پايـش ملی دريافت يـد و عملکردغده تيروئيد زنان باردار کشور در سال 1392
هدف : بر رسی وضعيت دريافت يد و عملکرد غده تيروئيد زنان باردار کشور
روش کار : در طی يک بر رسی مقطعی ملی تعداد 1200 زن باردار در تريمستر های مختلف بارداری از 12 استان کشور از آبان ماه تا بهمن ماه سال 1392 وارد مطالعه شدند
شاخص ها : ميانه يد ادرار T4, T3RU, FT4I, TSH, تيروگلوبولين و آنتی تيروئيد پر اکسيداز سرم مورد اندازه گيری قرار گرفتند.

22. نتايج کلی
Mean ±SD age of the cohort : 27 ± 7.2 years.
Mean ±SD gestational age:20.7 ± 10.0 weeks.
UIE (µg /L)
( میانه ید ادرار )
T4 (µg/dl)
TSH mIU/L
Min. 20
4.92
0.01
Max.
400
23.92
14.05
Mean
114
11.19
2.20
Median
87.3
10.88
1.95
Preliminary Results :

23. میانه ید ادرار کمتر از 100
میانه ید ادرار بین 100 و 150

24. نتیجه گیری
نتایج این مطالعه نشان داد که علیرغم دریافت ید کافی جامعه ایرانی جمعیت قابل توجه ای از زنان باردار ایرانی دچار کمبود متوسط ید بوده که نیاز به مکمل ید رسانی در این زمان دارند.

25. Conclusion
Pregnant women living in mild-moderate iodine deficient areas are at particularly high risk of being iodine deficient.
Clinical question
Iodine supplementation in pregnancy-
is it time?

26. How big is the problem? In Europe:
32 countries ( 1/3 of the global population) still have inadequate iodine intake.
In Europe:
►21 countries are iodine deficient in
pregnancy
►10 countries are iodine sufficient
►In 23 countries no data are available

27. Avon Longitudinal Study of Parents and Children ( ALSPAC) study in UK
What is the evidence for benefit from iodine supplementation in pregnancy in mild-moderate iodine deficiency?
Avon Longitudinal Study of Parents and Children ( ALSPAC) study in UK
1040 mother-child pairs
mild-to-moderate iodine deficiency
(UIC < 150 µg/l ) in the first trimester of pregnancy : odds of offspring IQ being in the lowest quartile
OR = 1.43; 95%CI ; P=0.03

28. Hynes et al. from Australia
Mild iodine deficiency during pregnancy is associated with reduced educational outcomes in the offspring: 9-year follow-up of the gestational iodine cohort. JCEM 2013
Taylor et al.
Impact of iodine supplementation in mild-to-moderate iodine deficiency: systematic review and meta-analysis. Eur J Endo. 2014

29. These studies imply there are potentially substantial benefits from correcting/ preventing even mild iodine deficiency in pregnancy.

30. Summary of relevant national and societal guidelines
Guidance
ATA
Australian Department of Health
ETA
US Teratology Society
Endocrine Society
All women who are planning to be pregnant or are pregnant or breastfeeding should supplement their diet with a daily oral supplement of 150 µg of iodine
(Endocrine Society : µg )
American Academy of Pediatrics
Spanish Endocrine Society
World Health Organization
Pregnant and lactating women should take a supplement containing adequate iodine to achieve a total of 250 µg iodine / day.
UK Department of Health
British Thyroid Association
No specific guidance on iodine intake

31. Key message
It is probable that, in mild-moderate iodine deficient countries, iodine supplementation during pregnancy and lactation may have substantial obstetric and offspring benefits and is economically advantageous.