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Research on Excessive Iodine Status in Pregnancy

Completed
Conditions
Thyroid Dysfunction, Antepartum
Excessive Iodine Status
Pregnancy Related
Neonatal Disorder
Interventions
Other: Dietary iodine intake restriction
Registration Number
NCT03422406
Lead Sponsor
Peking Union Medical College Hospital
Brief Summary

To explore main cause and health impact of iodine excess during pregnancy, we performed iodine evaluation for 390 consecutive pregnant women from January 1st, 2016 to December 31st, 2016. Among them, 18 women (4.62%) with apparently elevated urinary iodine concentration (UIC) were enrolled onto this study for subsequent follow-up. History of high iodine exposure was collected from all participants. Parameters about iodine status were monitors until termination of pregnancy, and dietary iodine intake condition and thyroid function were also evaluated.

Detailed Description

A prospective follow-up was arranged for the 18 pregnant women with excessive iodine status. History of iodine exposure (including hysterosalpingography (HSG) using an oil-soluble iodinated contrast medium, examination by computed tomography scan with contrast, administration of amiodarone, history of receiving radioiodine therapy, etc.) was collected from all participants. Evaluation of dietary iodine intake was performed through a 72-hour dietary recall.The serum iodine concentration (SIC) and urinary iodine concentration (UIC) were monitored continuously in the whole course of pregnancy. All subjects with excessive iodine load were recommended by nutritionists to have their dietary iodine intake restricted, and resume iodine-containing supplements and foods until the UIC\<250 μg/L and SIC≤90 μg/L. After delivery, maternal colostrum iodine concentration and neonatal iodine status (including neonatal UIC, condition of congenital hypothyroidism screening tests, and thyroid physical examination) were also assessed.

Recruitment & Eligibility

Status
COMPLETED
Sex
Female
Target Recruitment
18
Inclusion Criteria
  • Pregnant women with apparently elevated urinary iodine concentration (UIC ≥250μg/L) and serum iodine concentration (SIC>90μg/L) were enrolled in this study.
Exclusion Criteria
  • Subject who did not sign the informed consent or whose clinical date was not intact was excluded in our study.

Study & Design

Study Type
OBSERVATIONAL
Study Design
Not specified
Arm && Interventions
GroupInterventionDescription
Non-HH groupDietary iodine intake restrictionGroup (participants) without pre-gestational history of undergoing hysterosalpingography (HSG)
HH groupDietary iodine intake restrictionGroup (participants) with pre-gestational history of undergoing hysterosalpingography (HSG) using an oil-soluble iodinated contrast medium
Primary Outcome Measures
NameTimeMethod
composite neonatal outcome6-9 months post identification of maternal iodine excess

Apgar scores, birth weight of the neonates,and prevalence of thyroid dysfunction in neonates

prevalence of adverse pregnancy outcome6-9 months post identification of maternal iodine excess

prevalence of stillbirth, abortion and other adverse pregnancy outcome

Secondary Outcome Measures
NameTimeMethod
prevalence of neonatal iodine excesswithin 1 week after birth

urinary iodine concentration will be examined for all neonates born to women with iodine excess in pregnancy, and prevalence of neonatal urinary iodine concentration ≥ 200μg/L will be summarized.

prevalence of maternal thyroid dysfunction in pregnancythrough study completion, about 6-9 months post identification of maternal iodine excess

Laboratory reference ranges of TSH during pregnancy were 0.1\~2.5 mIU/L for the first trimester, 0.2\~3.0 mIU/L for the second trimester and 0.3\~3.0 mIU/L for the third trimester.Prevalence of TSH elevation during pregnancy will be summarized.

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