How should a 32‑week pregnant woman with an asthma exacerbation be treated?

Treatment of Asthma Exacerbation at 32 Weeks Gestation

Treat the asthma exacerbation aggressively with albuterol nebulization (2.5 mg every 20 minutes for 3 doses), add ipratropium (0.5 mg) for severe cases, and administer systemic corticosteroids (prednisone 40-60 mg daily) if symptoms do not rapidly improve—the risks of uncontrolled asthma far exceed any medication risks to mother or fetus. 1

Immediate Bronchodilator Therapy

• Administer albuterol 2.5 mg via nebulizer every 20 minutes for 3 doses, then every 1-4 hours as needed based on response. 1, 2
• Albuterol is the preferred short-acting beta-agonist in pregnancy because it has the most extensive safety data from over 6,667 pregnant women (including 1,929 with asthma) with no evidence of fetal harm. 3, 1, 4
• For severe exacerbations, add ipratropium bromide 0.5 mg combined with albuterol 2.5 mg in the same nebulizer every 20 minutes for 3 doses, then every 2-4 hours as needed. 1, 2

Systemic Corticosteroids

• Initiate oral prednisone 40-60 mg daily for 3-10 days if the exacerbation does not respond quickly to bronchodilators alone. 3, 1
• For severe exacerbations requiring hospitalization, use prednisone 120-180 mg/day divided into 3-4 doses for the first 48 hours, then 60-80 mg daily until peak expiratory flow reaches ≥70% of predicted or personal best. 3, 1
• Oral corticosteroids are as effective as intravenous when gastrointestinal absorption is intact—there is no advantage to IV administration. 1
• Do not withhold systemic corticosteroids due to pregnancy concerns; the hazards of uncontrolled asthma (maternal hypoxemia leading to fetal hypoxia, preeclampsia, preterm birth, low birth weight) far outweigh medication risks. 1, 4, 5

Maternal Monitoring During Treatment

• Maintain maternal arterial oxygen saturation above 95% to ensure adequate fetal oxygenation. 1
• Monitor maternal heart rate, blood glucose, and potassium levels, as albuterol can cause tachycardia, hyperglycemia, and hypokalemia. 1
• Consider arterial blood gas measurement in severe cases to assess maternal and fetal oxygenation status. 1

Fetal Surveillance at 32 Weeks

• Initiate serial ultrasound examinations immediately (at 32 weeks) and continue throughout the remainder of pregnancy to monitor fetal growth and detect intrauterine growth restriction. 3, 1, 4
• This surveillance is particularly important after a severe exacerbation and for women with moderate-to-severe or suboptimally controlled asthma. 3, 1
• Instruct the patient to monitor fetal activity closely. 3

Post-Exacerbation Management

• Perform spirometry after the acute episode to objectively confirm treatment response and guide controller therapy adjustments. 1
• Ensure the patient is on appropriate long-term controller therapy: budesonide is the preferred inhaled corticosteroid due to the most extensive pregnancy safety data (>2,500 infants studied with no increase in congenital malformations: 3.6% vs 3.5% background rate). 3, 4
• Step down therapy to the least medication necessary to maintain control only after stability is achieved. 1

Ongoing Pregnancy Management

• Schedule monthly evaluations of asthma symptoms and pulmonary function throughout the remainder of pregnancy, as asthma control can fluctuate unpredictably (one-third worsen, one-third improve, one-third remain stable). 1, 4, 6
• Involve the obstetrical care provider in ongoing assessment and monitoring. 1, 4
• If albuterol is needed more than twice weekly, this signals inadequate asthma control requiring initiation or escalation of inhaled corticosteroid therapy. 2, 4

Critical Pitfalls to Avoid

• Never reduce or discontinue asthma medications due to pregnancy concerns alone—uncontrolled asthma causes fetal hypoxia and increases risks of perinatal mortality, preeclampsia, preterm birth (46% higher risk of low birth weight), and intrauterine growth restriction. 1, 4, 7
• Do not assume the exacerbation will resolve without aggressive treatment; inadequate control poses greater risk than the medications used to treat it. 1, 5
• Avoid systemic epinephrine due to potential teratogenic effects and placental/uterine vasoconstriction. 8
• Do not delay systemic corticosteroids in moderate-to-severe exacerbations—early intervention prevents progression to critical asthma syndrome. 8, 9