What is the recommended treatment approach for a pregnant woman with asthma?

Treatment of Asthma in Pregnancy

Continue all asthma medications during pregnancy, as uncontrolled asthma poses far greater risks to both mother and fetus than any medication used to treat it. 1, 2

Core Management Principle

The fundamental approach is aggressive asthma control throughout pregnancy. Uncontrolled asthma increases risks of perinatal mortality, preeclampsia, preterm birth, low birth weight, and intrauterine growth restriction—risks that substantially exceed any theoretical medication concerns. 2, 3

Quick-Relief Therapy (All Patients)

Albuterol (salbutamol) is the preferred short-acting beta-agonist because it has the most extensive safety data from over 6,667 pregnant women, including 1,929 with asthma. 1, 2

Dosing for Acute Symptoms:

• 2-4 puffs via metered-dose inhaler as needed for symptoms 4, 1
• Up to 3 treatments at 20-minute intervals or single nebulizer treatment (2.5 mg) for acute symptoms 4, 1

Warning Sign for Inadequate Control:

• If albuterol is needed more than twice weekly, this signals inadequate asthma control requiring initiation or escalation of controller therapy 1, 2
• Using approximately one canister per month indicates poor control even if not using it daily 1

Controller Therapy (Persistent Asthma)

Inhaled corticosteroids are the preferred maintenance therapy and should be included in treatment regimens of all pregnant women with asthma. 2, 3

Preferred Agent:

Budesonide is the first-choice inhaled corticosteroid because it has the most extensive pregnancy safety data compared to other inhaled corticosteroids. 4, 2, 5

Dosing Ranges for Budesonide (DPI):

• Low dose: 200-600 mcg daily 4
• Medium dose: 600-1,200 mcg daily 4
• High dose: >1,200 mcg daily 4

Add-On Therapy:

Long-acting beta-agonists are the preferred add-on therapy to medium-to-high dose inhaled corticosteroids when needed for control. 5

Management of Acute Exacerbations

Treat exacerbations aggressively, as inadequate control poses greater risk than the medications. 6, 2

Initial Bronchodilator Therapy:

• Albuterol 2.5 mg via nebulizer every 20 minutes for 3 doses, then every 1-4 hours as needed 6, 2
• Alternative: 4-8 puffs via MDI every 20 minutes for 3 doses, then every 1-4 hours 6

For Severe Exacerbations:

Add ipratropium bromide to albuterol:

• Combination nebulizer: 2.5 mg albuterol + 0.5 mg ipratropium every 20 minutes for 3 doses, then every 2-4 hours 1, 6, 2
• Alternative: 4-8 puffs ipratropium via MDI as needed 6

Systemic Corticosteroids:

Add when exacerbations are not quickly controlled with bronchodilators:

• Outpatient: Prednisone 40-60 mg daily for 3-10 days 6
• Severe exacerbations: Prednisone 120-180 mg/day in 3-4 divided doses for 48 hours, then 60-80 mg/day until peak expiratory flow reaches 70% of predicted 6

Hospital Management:

• Consider arterial blood gas measurement in severe cases to assess maternal and fetal oxygenation 6
• Maintain maternal oxygen saturation above 95% for fetal well-being 6

Stepwise Approach

Step Up Criteria:

If control is not maintained, first review medication technique, adherence, and environmental control before escalating therapy. 4

Step Down Criteria:

Review treatment every 3-6 months; gradual stepwise reduction may be possible once control is achieved. 4

Specialist Referral:

Refer to an asthma specialist if there are difficulties controlling asthma or if Step 4 care is required. 4

Monitoring Throughout Pregnancy

Monthly evaluation of asthma control and pulmonary function is essential, as asthma course changes in approximately two-thirds of pregnant women (improves in one-third, worsens in one-third). 1, 6, 2

Obstetrical Involvement:

• The obstetrical care provider should be involved in assessment and monitoring during prenatal visits 6, 2
• Spirometry testing is recommended at initial assessment 1

Fetal Surveillance:

Serial ultrasounds starting at 32 weeks gestation should be considered for patients with moderate-to-severe asthma or suboptimally controlled asthma. 6, 2

Critical Pitfalls to Avoid

Never reduce or discontinue asthma medications due to pregnancy concerns. Uncontrolled asthma causes fetal hypoxia, which is far more harmful than medication exposure. 2, 3

Common Errors:

• Withholding inhaled corticosteroids due to unfounded teratogenicity fears 7
• Undertreating acute exacerbations during pregnancy 3
• Using oral decongestants in early pregnancy (potential association with rare birth defects) 6

Medication Safety Reassurance:

• Albuterol has Australian Therapeutic Goods Administration Category A classification, indicating compatibility during pregnancy 1
• The risk of structural anomalies with albuterol is similar to the general population 1
• Inhaled asthma medications have been used for many years without documented adverse fetal effects 1

Special Considerations

Medications with Limited Pregnancy Data:

Leukotriene modifiers have minimal human pregnancy data, though animal studies submitted to FDA are reassuring. 4

Labor and Delivery:

Beta-agonists may interfere with uterine contractility, so use during labor should be restricted to situations where benefits clearly outweigh risks. 8

Systemic Beta-Agonist Effects:

Systemic administration (oral or intravenous) can cause maternal and fetal tachycardia, maternal hyperglycemia, and neonatal hypoglycemia—use inhaled route preferentially. 1