Establishment of self-sequential longitudinal reference intervals of maternal thyroid function during pregnancy

Area of Science:

• Endocrinology
• Reproductive Medicine
• Clinical Chemistry

Background:

• Thyroid function undergoes significant changes during pregnancy, necessitating accurate reference intervals for maternal and fetal health.
• Existing reference ranges may not adequately capture the dynamic physiological shifts in thyroid hormones and antibodies throughout gestation.
• Establishing precise longitudinal data is crucial for timely diagnosis and management of thyroid disorders in pregnant individuals.

Purpose of the Study:

• To establish self-sequential longitudinal reference intervals for thyroid function in normal pregnant women.
• To compare thyroid function parameters between pregnant and non-pregnant control groups.
• To provide a more realistic and accurate basis for clinical diagnosis and therapy related to thyroid health during pregnancy.

Main Methods:

• Longitudinal collection of serum samples from 301 normal pregnant women across five stages: first trimester, second trimester, third trimester, prenatal, and postpartum.
• Quantification of thyroid stimulating hormone (TSH), free thyroxine (FT4), and thyroid peroxidase antibodies (TPO-Ab) using electrochemiluminescence immunoassay (ECL).
• Statistical analysis of data from pregnant women and 150 healthy non-pregnant controls using SPSS 13.0 software.

Main Results:

• Serum TSH levels were significantly lower in the first trimester of pregnancy and gradually increased, returning to non-pregnant levels by the prenatal phase.
• Serum FT4 levels remained consistently lower in pregnant women compared to non-pregnant controls throughout gestation.
• Serum TPO-Ab levels showed a significant increase in the third trimester and prenatal stages, with 6.5% of pregnant women testing positive.

Conclusions:

• The developed self-sequential longitudinal reference intervals more accurately reflect thyroid function dynamics during pregnancy.
• These new intervals can enhance the accuracy of clinical diagnosis and therapeutic interventions for thyroid conditions in pregnant women.
• Understanding these specific physiological changes is vital for optimizing obstetric and endocrine care.