Risk for neonatal hypoglycaemia and bradycardia after beta-blocker use during pregnancy or lactation: a systematic review and meta-analysis protocol

INTRODUCTION: Beta-blockers are often used during pregnancy to treat diseases such as pre-existing hypertension, arrhythmias or pregnancy-related hypertension. Since beta-blockers are able to cross the placenta and can pass into breast milk, they could potentially harm the neonate. Known potential neonatal side effects of maternal beta-blocker use are hypoglycaemia and bradycardia. This systematic review and meta-analysis aims to investigate the risk for neonatal hypoglycaemia and bradycardia after exposure to beta-blockers in utero or through lactation. METHODS AND ANALYSIS: We will conduct a systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A systematic electronic search will be conducted using EMBASE, Medline, Cochrane Central Register of Trials and Web of Science from initiation to April 2021. Our primary outcome will be the risk for hypoglycaemia or bradycardia in neonates exposed to beta-blockers in utero or through lactation in comparison with unexposed neonates. All articles will be screened by title and abstract twice by different independent review authors. Next, standardised methodological quality assessment will be conducted for each included article and finally a meta-analysis will be performed. ETHICS AND DISSEMINATION: Ethical approval is not required. The results of this study will help to assess the need for postnatal glucose and heart rate monitoring of the neonate after maternal beta-blocker exposure. Our findings will be communicated to the target audience through peer-reviewed publication. PROSPERO REGISTRATION NUMBER: CRD42021264269.