Metoprolol is a cardioselective beta blocker licensed for the treatment of hypertension, angina pectoris, cardiac arrhythmias, myocardial infarction, adjunctive management of thyrotoxicosis, and prophylaxis of migraine.
There are no published data on overall rates of congenital malformation following metoprolol use in pregnancy. Single case-control studies found no associations between first trimester metoprolol exposure and hypospadias and posterior cleft palate respectively. Further studies are required to corroborate these findings.
The limited available data currently provide no convincing evidence that exposure to metoprolol in utero has clinically relevant effects on fetal growth or increases the risk of preterm delivery. However, reduced fetal growth has been observed following gestational exposure to other beta blockers. Ongoing data collection is therefore required to fully assess this risk.
There are no controlled data comparing rates of miscarriage, stillbirth or neurodevelopmental outcomes following gestational metoprolol exposure. As such, it is not possible to predict the risks for these outcomes.
Use of beta blockers near term may result in beta-adrenoceptor blockade, leading to neonatal bradycardia, hypotension and hypoglycaemia. However, there are limited data on rates of these neonatal complications in metoprolol-exposed infants and the absolute risk therefore remains unquantified. Assessment of the neonate for these effects is advised until more robust data become available.
Exposure to metoprolol at any stage of pregnancy would not usually be regarded as medical grounds for termination. In pregnancies complicated by maternal hypertension and/or where metoprolol has been administered, careful monitoring of fetal growth is advised. Other risk factors may also be present in individual cases which may independently increase the risk of adverse pregnancy outcome. Clinicians are reminded of the importance of considering such factors when performing case-specific risk assessments.
Related document: Use of beta blockers in pregnancy
This is a summary of the full UKTIS monograph for health care professionals and should not be used in isolation. The full UKTIS monograph and access to any hyperlinked related documents is available to NHS health care professionals who are logged in.
If you have a patient with exposure to a drug or chemical and require assistance in making a patient-specific risk assessment, please telephone UKTIS on 0344 892 0909 to discuss the case with a teratology specialist.
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