ArticleChinese medical journal2019
Thyroid function of twin-pregnant women in early pregnancy.
Article in Chinese medical journal, 2019. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 5 papers, 1 of them a synthesis that pooled it.
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The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
5 citing papers in PubMed, 1 synthesis or guideline pooled it, 6 citations in OpenAlex.
- Maternal thyroid function in multiple pregnancies - a systematic review.Frontiers in endocrinology · 2022Pooled it
- Association between adverse obstetric history and perinatal outcomes in singleton and twin pregnancies: a retrospective study.Frontiers in medicine · 2026Article
- First-trimester thyroid reference intervals in twin pregnancy: establishment, diagnostic utility, and association with adverse outcomes.Frontiers in endocrinology · 2025Article
- Recommendations of the AGG (Working Group for Obstetrics, Department of Maternal Diseases) on How to Treat Thyroid Function Disorders in Pregnancy.Geburtshilfe und Frauenheilkunde · 2023Article
- [Thyroid function of first-trimester twin pregnant women and its association with preterm delivery].Beijing da xue xue bao. Yi xue ban = Journal of Peking University. Health sciences · 2021Article
Corrections and comments
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Authors and funding
10 authors at 2 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
backgroundSerum human chorionic gonadotrophin (hCG) is higher in twin than that in singleton pregnancies. As hCG stimulates the thyroid to produce more free thyroxine (FT4), which may lead to decreased thyroid-stimulating hormone (TSH) levels, the reference ranges of thyroid-related indicators may differ between singleton and twin pregnancies in the first trimester. This study aimed to establish reference ranges for thyroid-related indicators in early twin pregnancies and to compare them with singleton pregnancies.
methodsData of 820 twin-pregnant women were extracted from the established database of all pregnant women who delivered at Peking University First Hospital from October 2013 to May 2018; 160 who met National Academy of Clinical Biochemistry criteria were included to establish TSH and FT4 reference ranges. We screened 480 (3:1 paired) women with singleton pregnancies from the same database as controls. The Mann-Whitney test for TSH and FT4 levels was applied for comparisons between singleton and twin pregnancies.
resultsFirst-trimester reference ranges (4-12 gestational weeks) for twin pregnancies were: TSH 0.69 (0.01-3.35) mIU/L and FT4 16.38 (12.45-23.34) pmol/L. Median TSH was significantly lower at 7 to 12 gestational weeks than that at 4 to 6 gestational weeks (0.62 vs. 0.96 mIU/L, Z = -1.964, P = 0.049); FT4 was not significantly different between the two groups. Compared to singleton pregnancies, median TSH was significantly lower (0.69 vs. 1.27 mIU/L, Z = -6.538, P = 0.000), and FT4 was significantly higher (16.38 vs. 14.85 pmol/L, Z = -7.399, P = 0.000) in twin pregnancies in the first trimester.
conclusionsSpecific reference ranges for thyroid-related indicators for twin pregnancies are needed to avoid a misdiagnosis of thyroid dysfunction. Moreover, establishment of separate reference ranges for 4 to 6 and 7 to 12 gestational weeks in twin pregnancies may be considered.
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