Beta-blockers in pregnancy

Using beta blockers in with moderate hypertension in pregnancy:

• beta-blockers reduced the risk of developing severe hypertension
  
  
• beta-blockers did not reduce the risk of developing pre-eclampsia

Beta blockers may cause fetal bradycardia and possibly result in intrauterine growth retardation if used in the third trimester (1)

• there is ongoing debate about whether antihypertensive therapy impairs intra-uterine fetal growth, and if so, whether this effect is restricted to beta blocker therapy

A more recent review has stated (2):

• Exposure to beta blockers during early pregnancy does not appear to be associated with congenital malformations or heart malformations in offspring. Other organ-specific congenital malformations should be evaluated in further studies.

Notes:

• for women with severe hypertension [defined as a sustained systolic BP (sBP) of >=160 mmHg and/or a diastolic BP (dBP) of >=110 mmHg], there is consensus that antihypertensive therapy should be given to lower the maternal risk of central nervous system complications (1)
  • bulk of the evidence relates to parenteral hydralazine and labetalol, or to oral calcium channel blockers such as nifedipine capsules
  • there is, however, no consensus regarding management of non-severe hypertension (defined as a sBP of 140-159 mmHg or a dBP of 90-109 mmHg), because the relevant randomized trials have been underpowered to define the maternal and perinatal benefits and risks
    • although antihypertensive therapy may decrease the occurrence of BP values of 160-170/100-110 mmHg, therapy may also impair fetal growth

Reference:

• Magee LA et al. How to manage hypertension in pregnancy effectively. Br J Clin Pharmacol. 2011 Sep;72(3):394-401
• Wu Y et al. Risk of congenital malformations in offspring of women using beta-blockers during early pregnancy: An updated meta-analysis of observational studies. Br Journ Pharmacol. 2021; 87(3): 806-15