What is the preferred inhaled corticosteroid (ICS) for asthma management during pregnancy?

Preferred Inhaled Corticosteroid in Pregnancy

Budesonide is the preferred inhaled corticosteroid for asthma management during pregnancy due to the most extensive safety data available in pregnant women, showing no increased risk of congenital malformations or adverse perinatal outcomes. 1

Primary Recommendation

• Budesonide should be the first-choice ICS when initiating inhaled corticosteroid therapy in pregnant women with persistent asthma 1
• This preference is based on reassuring data from over 6,600 infants exposed to budesonide during pregnancy, with no clinically significant effects on fetal outcomes 2
• Budesonide is the only inhaled corticosteroid classified as FDA Pregnancy Category B (now equivalent to having no evidence of risk in humans), while all other ICS are Category C 3, 4
• Large Swedish registry data (2,534 infants) showed congenital malformation rates of 3.6-3.8%, comparable to the general population rate of 3.5% 3

When to Continue Other ICS

However, if a pregnant woman's asthma was well-controlled on a different ICS prior to pregnancy, that medication should be continued rather than switched to budesonide. 1

• Switching formulations may jeopardize asthma control, which poses greater risk than continuing the current effective ICS 1
• No data indicate that other ICS preparations (beclomethasone, fluticasone, ciclesonide, mometasone) are unsafe during pregnancy 1
• The priority is maintaining optimal asthma control, as uncontrolled asthma increases risks of preeclampsia, prematurity, low birth weight, and perinatal mortality 3

Stepwise Approach by Asthma Severity

Mild Persistent Asthma (Step 2)

• Low-dose budesonide daily is the preferred long-term controller 1, 5
• Alternative agents (cromolyn, leukotriene receptor antagonists, theophylline) are less effective than ICS and not preferred 1

Moderate Persistent Asthma (Step 3)

• Either low-dose budesonide plus long-acting beta-agonist OR medium-dose budesonide 1, 5
• Both options are acceptable; choice depends on individual response 1

Severe Persistent Asthma (Step 4)

• High-dose budesonide is preferred 1, 5
• Add systemic corticosteroids if high-dose ICS insufficient, as severe uncontrolled asthma poses definite maternal-fetal risk 1

Supporting Evidence Quality

The recommendation for budesonide is strengthened by:

• Multiple international guidelines (NAEPP 2004, ERS/TSANZ 2020) consistently recommending budesonide as preferred 1
• FDA drug labeling specifically noting reassuring pregnancy data 3
• A randomized controlled trial of 313 pregnancies showing no difference in adverse outcomes between budesonide and placebo (19% vs 23% adverse outcomes, respectively) 6
• Beclomethasone also has substantial pregnancy data and is considered an acceptable alternative 1

Critical Clinical Pitfalls to Avoid

• Never discontinue ICS during pregnancy due to safety concerns - uncontrolled asthma poses far greater risk to mother and fetus than ICS use 5, 4, 7
• Do not switch a well-controlled patient from another ICS to budesonide - maintaining control is paramount 1
• Do not undertreated exacerbations - aggressive management with systemic corticosteroids when needed is safer than allowing maternal hypoxia 1, 5
• Monthly monitoring of asthma control is essential, as asthma improves in one-third and worsens in one-third of pregnant women 5

Disease-Associated Risks Without Treatment

• Poorly controlled asthma increases risk of preeclampsia, prematurity, low birth weight, and small-for-gestational-age infants 3
• It is safer to treat pregnant women with asthma medications than to allow symptoms and exacerbations 5, 4
• The major fetal risk is maternal hypoxia from uncontrolled bronchospasm, not from appropriate medication use 8