Digestive Diseases and Sciences

, 54:1835 | Cite as

The Safety of Histamine 2 (H2) Blockers in Pregnancy: A Meta-analysis

  • Simerpal Kaur Gill
  • Lisa O’Brien
  • Gideon Koren
Original Article


Heartburn and acid reflux increase the severity of nausea and vomiting of pregnancy, and may lead to more serious medical conditions. The fetal safety of histamine 2 (H2) blockers, the most common antireflux medication, during pregnancy needs to be determined. The aim herein is to determine the fetal safety of H2 blockers during pregnancy through systematic review. All original research assessing the safety of H2 blockers in pregnancy was sought. Data included congenital malformations, spontaneous abortions, preterm delivery, and small for gestational age. A random-effects model combined results. With data from 2,398 exposed and 119,892 nonexposed to H2 blockers, overall odds ratio was 1.14 [0.89, 1.45]. Further analysis revealed no increased risks for spontaneous abortions, preterm delivery, and small for gestational age with odds ratios and 95% confidence intervals (CIs) of 0.62 [0.36–1.05], 1.17 [0.94, 1.147], and 0.28 [0.06, 1.22], respectively. H2 blockers can be used safely in pregnancy.


H2 blockers Acid reflux GERD Pregnancy Malformations 



Motherisk NVP helpline is supported by an unrestricted grant from Duchesnay, Inc. Canada. GK is holder of the Research Leadership for Better Pharmacotherapy during Pregnancy and Lactation (Hospital for Sick Children) and the Ivey Chair in Molecular Toxicology (Department of Medicine, University of Western Ontario).


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Copyright information

© Springer Science+Business Media, LLC 2008

Authors and Affiliations

  • Simerpal Kaur Gill
    • 1
    • 2
  • Lisa O’Brien
    • 1
    • 3
  • Gideon Koren
    • 1
    • 2
    • 3
  1. 1.The Motherisk Program, The Hospital for Sick ChildrenTorontoCanada
  2. 2.Department of PharmacologyUniversity of TorontoTorontoCanada
  3. 3.Institute of Medical Science, University of TorontoTorontoCanada

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