Longitudinal trajectories of gestational thyroid function: A new approach to better understand changes in thyroid function

Victor Pop*, Maarten Broeren, Hennie Wijnen, Joyce Endendijk, Anneloes van Baar, Wilmar Wiersinga, Graham R. Williams

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

7 Citations (Scopus)

Abstract

Context:  

Most studies of thyroid function changes during pregnancy use a cross-sectional design comparing means between groups rather than similarities within groups.

Objective:

Latent class growth analysis (LCGA) is a novel approach to investigate longitudinal changes that provide dynamic understanding of the relationship between thyroid status and advancing pregnancy.

Design: 

Prospective observational study with repeated assessments.

Setting: 

General community.

Patients: 

Eleven hundred healthy women were included at 12 weeks' gestation.

Main Outcome Measures: 

The existence of both free T4 (fT4) and TSH trajectories throughout pregnancy determined by LCGA.

Results: 

LCGA revealed three trajectory classes. Class 1 (n = 1019; 92.4%), a low increasing TSH reference group <had a gradual increase in TSH throughout gestation (from 1.1 to 1.3 IU/L). Class 2 (n = 30; 2.8%), a high increasing TSH grouP <displayed the largest increase in TSH (from 1.9 to 3.3 IU/L). Class 3 (n = 51; 4.6%), a decreasing TSH grouP <had the largest fall in TSH (from 3.2 to 2.4 IU/L). Subclinical hypothyroidism at 12 weeks occurred in up to 60% of class 3 women and was accompanied by elevated thyroid peroxidase antibodies (TPO-Ab) titers (50%) and a parental history of thyroid dysfunction (23%). In class 2, 70% of women were nulliparous compared with 46% in class 1 and 49% in class 3.

Conclusions:

LCGA revealed distinct trajectories of longitudinal changes in fT4 and TSH levels during pregnancy in 7.4% of women. These trajectories were correlated with parity and TPO-Ab status and followed patterns that might reflect differences in pregnancy-specific immune tolerance between nulliparous and multiparous women.

Original languageEnglish
Pages (from-to)2889-2900
JournalJournal of Clinical Endocrinology and Metabolism
Volume103
Issue number8
DOIs
Publication statusPublished - 2018

Keywords

  • REGULATORY T-CELLS
  • IRON-DEFICIENCY
  • EARLY-PREGNANCY
  • GENERATION-R
  • FETAL SEX
  • MANAGEMENT
  • DISEASE
  • GROWTH
  • ASSOCIATION
  • POSTPARTUM

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