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ORIGINAL RESEARCH article

Front. Endocrinol.
Sec. Developmental Endocrinology
Volume 15 - 2024 | doi: 10.3389/fendo.2024.1431621
This article is part of the Research Topic Understanding the impact on metabolic health of interactions between pre- and post-natal nutrition, sex, growth and endocrine development View all 5 articles

Fetal Sexual Dimorphism of Maternal Thyroid Function Parameters During Pregnancy, A Single Center Retrospective Real-world Study

Provisionally accepted
Meiqin Wu Meiqin Wu 1Chunping Hu Chunping Hu 2Dan Huang Dan Huang 1Hao Ying Hao Ying 3*Jing Hua Jing Hua 1*
  • 1 Department of Women and Children's Health Care, Shanghai First Maternity and Infant Hospital, Shanghai, China
  • 2 Department of Spine Surgery, Honghui Hospital, Xi'an Jiaotong University, Xi'an, China
  • 3 Department of Obstetrics, Shanghai First Maternity and Infant Hospital, Shanghai, Shanghai Municipality, China

The final, formatted version of the article will be published soon.

    Thyroid function during pregnancy fluctuates with gestational weeks, seasons and other factors. However, it is currently unknown whether there is a fetal sex-specific thyroid function in pregnant women. The purpose of this study was to investigate the fetal sex differences of maternal thyroid-stimulating hormone (TSH) and free thyroxine (FT4) in pregnant women. This single-center retrospective real-world study was performed by reviewing the medical records of pregnant women who received regular antenatal health care and delivered liveborn infants in Shanghai First Maternity and Infant Hospital (Pudong branch), from Aug. 18, 2013 to Jul. 18, 2020. Quantile regression was used to evaluate the relationship between various variables and TSH and FT4 concentrations. The quantile regression also evaluated the sex impact of different gestational weeks on the median of TSH and FT4. A total of 69,243 pregnant women with a mean age of 30.36 years were included. 36197 (52.28%) deliveries were boys.In the three different trimesters, the median levels (interquartile range) of TSH were 1.18 (0.66, 1.82) mIU/L and 1.39 (0.85, 2.05) mIU/L, 1.70 (1.19, 2.40) mIU/L; and the median levels (interquartile range) of FT4 were 16.63 (15.16, 18.31) pmol/L, 14.09 (12.30, 16.20) pmol/L and 13.40 (11.52, 14.71) pmol/L, respectively. The maternal TSH upper limit of reference ranges was decreased more in mothers with female fetuses during gestational weeks 7 to 12, while their FT4 upper limit of the reference ranges was increased more than those with male fetuses. After model adjustment，the median TSH level was 0.11 mIU/L lower (P <0.001), and FT4 level was 0.14 pmol/L higher (P <0.001) for mothers with female fetuses than those with male fetuses during gestational weeks 9 to 12. We identified sexual dimorphism in maternal thyroid function parameters, especially during 9-12 weeks of pregnancy. Based on previous research, we speculated that it may be related to the higher HCG levels of mothers who were pregnant with girls during this period. However, longitudinal studies are needed to determine if fetal sex differences impact the maternal thyroid function across pregnancy.

    Keywords: Fetal sex, Thyroid function, Pregnancy, Reference intervals, realworld study

    Received: 12 May 2024; Accepted: 01 Aug 2024.

    Copyright: © 2024 Wu, Hu, Huang, Ying and Hua. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence:
    Hao Ying, Department of Obstetrics, Shanghai First Maternity and Infant Hospital, Shanghai, 200000, Shanghai Municipality, China
    Jing Hua, Department of Women and Children's Health Care, Shanghai First Maternity and Infant Hospital, Shanghai, China

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