Inhaled muscarinic antagonists during pregnancy in women with asthma: case series from a Dutch prospective...

A large proportion of women with asthma experience worsening of asthma during pregnancy. Well-controlled asthma during pregnancy decreases the risk of maternal and fetal complications. Long-acting muscarinic antagonists (LAMAs) are part of treatment guidelines for poorly controlled asthma. There are no clinical safety data available on LAMA and short-acting muscarinic antagonists (SAMAs) use in pregnancy.Objective: The aim was to evaluate asthma control and pregnancy outcomes in pregnant women with asthma using muscarinic antagonists.Methods: A prospective observational cohort of pregnant women with asthma referred to the asthma pregnancy outpatient clinic of the Haga Hospital, between 2018 and 2023, was obtained and retrospectively analyzed. Women using muscarinic antagonists were included. Outcomes were asthma control, asthma exacerbations and pregnancy outcomes.

Fourteen (8.9%) of 158 recruited pregnant women used muscarinic antagonists. Most women had poor asthma control with a mean (±SD) Asthma Control Questionnaire (ACQ) score of 2.4 (±1.3). Six (43%) women experienced an asthma exacerbation. One woman using LAMA throughout pregnancy had pre-eclampsia resulting in preterm birth, low birth weight and neonatal hospitalization. Another child was born with low birth weight and was small for gestational age. Two women developed maternal fever.Conclusions: A minority of women with asthma used muscarinic antagonists during pregnancy. Despite the use of muscarinic antagonists, asthma control remained poor during pregnancy. There were no major adverse pregnancy outcomes or congenital malformations in this case series. Since well-controlled asthma during pregnancy leads to fewer complications, pregnant woman with poorly controlled asthma on inhaled corticosteroid (ICS)/long-acting beta-2-agonist (LABA) should be encouraged to continue add-on asthma medication.