Thyroid structure, function and iodine status by pregnancy trimester in Harbin, China.

Area of Science:

• Endocrinology
• Reproductive Health
• Public Health Nutrition

Background:

• Thyroid disease during pregnancy poses significant risks to fetal development.
• Limited data exists on thyroid disease prevalence and contributing factors in pregnant women in Harbin, China.
• Iodine intake, assessed via urine iodine concentration (UIC), is crucial for thyroid health.

Purpose of the Study:

• To investigate the relationship between urine iodine concentration (UIC) and thyroid structure and function during pregnancy in Harbin.
• To determine the incidence and types of thyroid abnormalities in pregnant women across different trimesters.

Main Methods:

• Prospective data collection from 24,000 pre-pregnant women (Jan 2017-Aug 2019).
• Measurement of serum thyroid hormones and thyroid ultrasonography.
• Assessment of gestational age and UIC in 500 participants with newly developed thyroid abnormalities.

Main Results:

• Significant differences in abnormal thyroid structure and function incidence across trimesters (p<0.05).
• Thyroid nodular lesions and positive thyroid peroxidase antibodies (TPOAb) were the most frequent abnormalities.
• Median UIC decreased significantly with advancing gestational age (p<0.001), but no significant association was found between UIC levels and thyroid abnormalities (p>0.05).

Conclusions:

• Thyroid structural and functional abnormalities are common in the second and third trimesters of pregnancy in Harbin.
• Thyroid nodular lesions and positive TPOAb are the most prevalent thyroid issues.
• Declining median UIC with gestation suggests iodine deficiency among pregnant women in Harbin.