Iodine Impact on Thyroid Function and Psychomotor Development, Observational Study in the Portuguese Minho Region

Study Overview
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Brief Summary
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Full intellectual capabilities are achieved only if crucial nutrients are present during development. Iodine deficiency is the most common cause of preventable brain harm in infants. Because of its critical need during pregnancy, several countries implemented programs of iodine supplementation in preconception and pregnancy. In 2013, the prevalence of iodine deficiency in Portugal has led health authorities to issue a recommendation for iodine supplementation. This study aims to evaluate the impact of iodine supplementation on maternal and fetal iodine status and thyroid function, obstetric outcomes, quality of breast milk and child psychomotor development. It also intends to evaluate whether the time of iodine supplementation initiation influences all the above-mentioned parameters. The novelty and relevance of this study reside on the number of women/child and on the extent of health parameters that will be evaluated. The information collected will contribute to the detailed characterization of thyroid hormone homeostasis throughout pregnancy and its relationship with iodine supplementation (including time of initiation). The data will provide evidence on whether this iodine supplementation strategy impacted on iodine sufficiency of the mother and the newborns, or if it needs re-evaluation.

Detailed Description
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Iodine is essential for intellectual development. Its deficiency, alone, is the most frequent cause of preventable brain harm in infants. Iodine is required to synthesize thyroid hormones, key components of central nervous system development. Because of its relevance in pregnancy, several countries have implemented iodine supplementation programs in preconception, pregnancy and lactation. Iodine deficiency has been previously shown in women of childbearing age in Portugal. Because of this, since 2013 the National Health Authorities have recommended supplementing iodine (200 ug/day) in preconception, pregnant and lactating women. However, the latest Cochrane review on the subject does not allow to conclude on whether iodine supplementation strategies implemented to date are efficient. Therefore, this study is of great public health interest. The objectives are to: Evaluate whether the new policy of recommending iodine supplementation in preconception, throughout pregnancy and during lactation impacted on the prevalence of iodine deficiency in the Minho region of Portugal when compared to the same population before the recommendation. Evaluate whether the time of initiation of iodine supplementation (if any) influences the serum levels of thyroid hormones in the three trimesters of pregnancy. Evaluate whether the serum levels of thyroid hormones in the first trimester of pregnancy predict psychomotor development of the newborn at 12 months of age. To achieve these aims the investigators will follow: i) 304 women longitudinally, before, during the three trimesters of pregnancy (primary care Health Centres), at delivery and three months after delivery, ii) their children at birth, 3 and 12 months of age; ii) perform a detailed evaluation of parameters of thyroid function (mother and child) and of psychomotor development of the newborns. Investigators expect to provide detailed characterization of thyroid hormone homeostasis before and throughout pregnancy, their relation with iodine supplementation (and its timing of administration, if any) and with thyroid hormone parameters and psychomotor development of the newborn. With 6 years passed since the beginning of recommendation on iodine supplementation, this is an appropriate time to assess its effectiveness. The high number of samples and parameters to analyze make this a high-power study to support public health policies.

Official Title
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Observational Study on the Impact of Iodine Supplementation on Maternal and Child's Thyroid Hormone Homeostasis and on the Child's Psychomotor Development, in the Portuguese Minho Region (IodineMinho)

Conditions
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Iodine Deficiency, Thyroid, Pregnancy Related, Psychomotor Impairment, Hypothyroidism in Pregnancy, Nutrient Deficiency

Intervention / Treatment
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* Dietary Supplement: Iodine supplementation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Women of who intend to become pregnant or are pregnant, able to read, write and provide informed consent Exclusion Criteria: Women transferred from outside the study health centres during pregnancy and women taking iodine supplementation before recruitment. Women not intending to deliver at Hospital de Braga.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Pregnant and pregnant to be on iodine supplementation<br>Women in preconception, pregnant and lactating, receiving iodine supplementation | Dietary Supplement: Iodine supplementation<br>* Recommendation, issued by the National Health Authorities, on supplementing with iodine (200 ug/day) women during preconception, pregnancy and lactation.<br>|
| Pregnant and pregnant to be not on iodine supplementation<br>Women in preconception, pregnant or lactating, not receiving iodine supplementation | |
| Women of childbearing age<br>Women of childbearing age not planning to become pregnant. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Prevalence of iodine deficiency in pregnant women and in women of childbearing age in the Minho region | Urinary iodine. | At baseline in women recruited for pregnancy follow-up and in women in childbearing age not planning to become pregnant. | 
| Impact of iodine supplementation on maternal serum parameters of thyroid function and urinary iodine in the first trimester of pregnancy | Serum thyroid hormones (TSH, total and free T4, total and free T3, thyroxine-binding globulin, human chorionic gonadotropin, thyroglobulin, anti-thyroglobulin, anti-thyroperoxidase), urinary iodine. | First trimester of pregnancy | 
| Bayley scale assessed psychomotor development at one year of age | Bayley psychomotor development scale | One year of age | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Serum parameters of thyroid function, urinary iodine and thyroid ultrasound characterization throughout pregnancy | Serum thyroid hormones (TSH, total and free T4, total and free T3, thyroxine-binding globulin, human chorionic gonadotropin, thyroglobulin, anti-thyroglobulin, anti-peroxidase), urinary iodine, thyroid ultrasound. | Serum thyroid hormones and urinary iodine before iodine supplementation (if any), 1st, 2nd, 3rd trimesters of pregnancy, after delivery. Thyroid ultrasound at baseline, 3rd trimester and 3 months after delivery. | 
| Serum parameters of thyroid function, urinary iodine and thyroid ultrasound characterization of newborns | Serum thyroid hormones (TSH and eventually total and free thyroxine as retrieved from the neonatal newborn screening) and urinary iodine. | One to 3 days of age (if full term babies), 1 to 3 days and 4th week of age (in premature and low birth weight babies). | 
| Iodine and energy composition of human milk 3 months after delivery | Iodine and energy composition (total proteins, lipids and carbohydrates). | Three months after delivery | 
| Fetal heart rate and thyroid volume at age 3 months | Fetal cardiotocography and thyroid ultrasound. | Fetal cardiotocography at 36-40 weeks of gestation and thyroid ultrasound at 3 months of age. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Iodine, Human milk, Maternal health, Nutritional assessment, Thyroid hormones, Pregnancy, Population health, Congenital hypothyroidism, Psychomotor development