Levothyroxine and pregnancy outcomes in women with subclinical hypothyroidism

  • Nazarpour S & al.
  • Arch Gynecol Obstet
  • 10 Aug 2019

  • curated by Sarfaroj Khan
  • UK Clinical Digest
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  • In pregnant women with sub-clinical hypothyroidism (SCH), levothyroxine treatment is associated with a reduced risk for pregnancy loss and increased chances for live birth rate.
  • These findings are not based on randomised controlled trials (RCTs) and should be interpreted with caution.

Why this matters

  • SCH is associated with adverse pregnancy outcomes.
  • There is still uncertainty regarding the prescription of levothyroxine therapy in preventing adverse outcomes.

Study design

  • 13 studies (7 cohort studies and 6 RCTs) including 11,503 participants identified after a search across PubMed, Web of Science, Wiley, Google Scholar, ScienceDirect, and Scopus databases.
  • Funding: None.

Key results

  • Pregnant women with SCH treated with levothyroxine vs those treated with placebo had significantly:
    • lower chances of pregnancy loss (OR, 0.78; 95% CI, 0.66-0.94; I2=0%; P<.05 and>
    • higher chances of live birth rates (OR, 2.72; 95% CI, 1.44-5.11; I2=25%; P<.05>
  • Pregnant women with SCH administered levothyroxine vs euthyroid women had a higher risk for preterm labour (OR, 1.82; 95% CI, 1.14-2.91; I2=0%).
  • No significant differences were observed between patients treated with levothyroxine vs those with placebo for:
    • adverse maternal complications (OR, 1.038; 95% CI, 0.817-1.319),
    • obstetrical haemorrhage (OR, 0.973; 95% CI, 0.575-1.644),
    • preterm/low birth weight/oligohydramnios, (OR, 0.933; 95% CI, 0.821-1.061), and
    • adverse neonatal complications (OR, 0.919; 95% CI, 0.734-1.150).


  • No universal cut-off value for thyroid stimulating hormones in the diagnosis of SCH.

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