CC BY 4.0 · Rev Bras Ginecol Obstet 2023; 45(10): e557-e561
DOI: 10.1055/s-0043-1776028
Original Article
Obstetrics

Thyroid Volume in Pregnancy is Associated with Parity, Gestational Age, and Body Mass Index in an Iodine-sufficient Area

O volume tireoidiano em gestantes está associado à paridade, idade gestacional e índice de massa corporal em uma área suficiente em iodo
1   Endocrinology Postgraduate Program, Medical School, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
,
1   Endocrinology Postgraduate Program, Medical School, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
,
1   Endocrinology Postgraduate Program, Medical School, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
,
1   Endocrinology Postgraduate Program, Medical School, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
,
1   Endocrinology Postgraduate Program, Medical School, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
,
1   Endocrinology Postgraduate Program, Medical School, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
,
2   Radiology Division, Hospital Municipal Rocha Maia, Rio de Janeiro, RJ, Brazil
,
1   Endocrinology Postgraduate Program, Medical School, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
,
1   Endocrinology Postgraduate Program, Medical School, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
,
1   Endocrinology Postgraduate Program, Medical School, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
,
1   Endocrinology Postgraduate Program, Medical School, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
,
1   Endocrinology Postgraduate Program, Medical School, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
,
1   Endocrinology Postgraduate Program, Medical School, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
› Author Affiliations

Abstract

Objective We compared thyroid volume (TV) and presence of nodular goiter (NG) in pregnant vs. non-pregnant women in an iodine-sufficient area. We also evaluated the relationship between gestational age, parity, and TV in the pregnant women group, and determined the 2.5th and 97.5th percentiles of normal TV in pregnancy.

Methods This cross-sectional study included 299 healthy women (216 pregnant) without previous thyroid diseases. Thyroid ultrasounds were performed and compared between pregnant and non-pregnant women. The range of normal distribution of TV (2.5th and 97.5th percentiles) in pregnancy was determined after excluding individuals with positive thyroid antibodies, NG, and/or abnormal serum thyrotropin (TSH) or free thyroxine (FT4).

Results Thyroid volume was larger among pregnant compared to non-pregnant women (8.6 vs 6.1 cm3; p < 0.001) and was positively correlated with gestational age (rs = 0.221; p = 0.001), body mass index (BMI, rs 0.165; p = 0.002), and FT4 levels (rs 0.118 p = 0.021). Nodular goiter frequency did not differ between the two groups. There was a negative correlation between TV and TSH (rs -0.13; p = 0.014). Thyroid volume was lower among primiparous compared to multiparous patients (7.8 vs 8.9; p < 0.001) and was positively correlated with parity (rs 0.161; p = 0.016). The 2.5th and 97.5th percentiles of TV were 4.23 and 16.47 cm3, respectively.

Conclusion Thyroid volume was higher in pregnant compared to non-pregnant women and was positively related to parity, BMI, and gestational age in a normal iodine status population. Pregnancy did not interfere with the development of NG.

Resumo

Objetivo Comparamos o volume tireoidiano (VT) e a presença de bócio nodular (BN) em mulheres grávidas e não grávidas em uma área suficiente em iodo. Também avaliamos a relação entre idade gestacional, paridade e VT no grupo de gestantes e determinamos os percentis 2,5 e 97,5 de VT normal na gestação.

Métodos Este estudo transversal incluiu 299 mulheres saudáveis (216 grávidas) sem doenças tireoidianas prévias. Ultrassonografias de tireoide foram realizadas e comparadas entre mulheres grávidas e não grávidas. A faixa de distribuição normal de VT (percentis 2,5 e 97,5) na gestação foi determinada após a exclusão de indivíduos com anticorpos tireoidianos positivos, BN e/ou tireotropina sérica (TSH) ou tiroxina livre (T4L) anormais.

Resultados O VT foi maior entre as gestantes em comparação com as mulheres não grávidas (8,6 vs 6,1 cm3; p < 0,001) e foi positivamente correlacionado com a idade gestacional (rs = 0,221; p = 0,001), índice de massa corporal (IMC, rs 0,165; p = 0,002) e níveis de T4L (rs 0,118 p = 0,021). A frequência de BN não diferiu entre os dois grupos. Houve correlação negativa entre VT e TSH (rs -0,13; p = 0,014). O VT foi menor entre as primíparas em comparação com as multíparas (7,8 vs 8,9; p < 0,001) e foi positivamente correlacionado com a paridade (rs 0,161; p = 0,016). Os percentis 2,5 e 97,5 de VT foram 4,23 e 16,47 cm3, respectivamente.

Conclusão O VT foi maior em gestantes em comparação com mulheres não grávidas e foi positivamente relacionado à paridade, IMC e idade gestacional em uma população com status iódico normal. A gravidez não interferiu no desenvolvimento de BN.

Contributions

All authors contributed to the design of the study, were involved in the data collection, data analysis and/or interpretation. Also, all authors contributed to the writing/substantive editing and review of the manuscript and approved the final draft of the manuscript.




Publication History

Received: 06 December 2022

Accepted: 01 August 2023

Article published online:
09 November 2023

© 2023. Federação Brasileira de Ginecologia e Obstetrícia. This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/)

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