Comparison of the safety between propylthiouracil and methimazole with hyperthyroidism in pregnancy: A systematic review and meta-analysis

PLoS One. 2023 May 19;18(5):e0286097. doi: 10.1371/journal.pone.0286097. eCollection 2023.

Abstract

Objective: The purpose of this meta-analysis was to assess the safety of the anti-thyroid drugs (ATDs) propylthiouracil (PTU) and methimazole (MMI) in the treatment of hyperthyroidism during pregnancy.

Method: From inception until June 2, 2022, all available studies were searched in PubMed, Web of Science, Cochrane, EBSCO, Embase, Scopus, and CNKI.

Result: Thirteen articles satisfying the inclusion criteria were examined. Our meta-analysis indicated that pregnant women treated with MMI had a higher risk of congenital anomalies than those treated with PTU (OR 0.80, 95%CI 0.69-0.92, P = 0.002, I2 = 41.9%). Shifting between MMI and PTU during pregnancy did not reduce the risk of birth defects compared to PTU alone (OR 1.18, CI 1.00 to 1.40, P = 0.061, I2 = 0.0%). There were no statistically significant differences in hepatotoxicity (OR 1.54, 95%CI 0.77-3.09, P = 0.221, I2 = 0.0%) or miscarriage (OR 0.89, 95%CI 0.72-1.11, P = 0.310, I2 = 0.0%) between PTU and MMI exposure.

Conclusion: The study confirmed propylthiouracil is a safer alternative to methimazole for treating hyperthyroidism in pregnant women, and it is appropriate to treat maternal thyroid disease with PTU during the first trimester of pregnancy. However, it is not clear whether switching between propylthiouracil and methimazole is a better option than treating PTU alone during pregnancy. Further studies on this matter may be needed to develop new evidence-based guidelines for the treatment of pregnant women with hyperthyroidism.

Publication types

  • Meta-Analysis
  • Systematic Review

MeSH terms

  • Abortion, Spontaneous*
  • Antithyroid Agents / adverse effects
  • Female
  • Humans
  • Hyperthyroidism* / drug therapy
  • Methimazole / adverse effects
  • Pregnancy
  • Pregnancy Complications* / drug therapy
  • Propylthiouracil / adverse effects

Substances

  • Methimazole
  • Propylthiouracil
  • Antithyroid Agents

Grants and funding

The author(s) received no specific funding for this work.