Asthma in pregnancy
Asthma is a common chronic disease complicating pregnancy whose course is unpredictable (roughly a third of patients worsen, a third improve, a third stay the same), and the dominant maternal and fetal risk is hypoxemia from an undertreated exacerbation, not the medications used to control it. Diagnosis and severity classification are unchanged from the general population; management follows the same stepped controller ladder plus specific fetal-growth and peak-flow monitoring for moderate-to-severe disease.
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What this article covers
- Overview
A common chronic disease pregnancy can push either way: this article covers the pregnancy-specific course, risk, drug safety, and monitoring of asthma, not general pathophysiology or diagnosis (see…
- Epidemiology
General-population prevalence carries into pregnancy: self-reported asthma affects roughly 7%-19% of adults, so many patients enter pregnancy with pre-existing disease.
- Risk factors
Poor asthma control at the start of pregnancy: the strongest predictor of worsening asthma during gestation; document baseline control at the first prenatal visit.
- Pathophysiology
Hypoxemia, not medication, is the operative threat: the major risk to mother and fetus is hypoxemia secondary to an asthma exacerbation, not the medications used to treat asthma; this fact anchors every treatment decision.
- Clinical features
Same hallmark symptoms as the general population: episodic wheeze, cough, and shortness of breath, often worse at night and triggered by allergens, exercise, infection, or irritants (see asthma pathophysiology and diagnosis).
- Differential diagnosis
Pulmonary embolism: dyspnea and hypoxia, elevated baseline risk since pregnancy is hypercoagulable; lacks dominant wheeze, often unilateral leg swelling; confirmed by CT pulmonary angiography or V/Q scan.
- Diagnosis
Severity/control are classified with the same criteria used outside pregnancy: the NAEPP framework grades disease intermittent or persistent (mild, moderate, severe), assigning the most severe…
- Management
First, continue (or start) controller therapy at the lowest step that maintains control, using the identical NAEPP stepped ladder used outside pregnancy (see asthma management for the full step 1-6…
- Complications
Maternal and fetal hypoxemia during a severe exacerbation: the acute, most dangerous complication, and the reason standard therapy should never be delayed or withheld in pregnancy; it can trigger…
- Prognosis
Good control predicts a good outcome: patients who maintain pre-pregnancy control through gestation have outcomes comparable to nonasthmatic pregnancies; the rule of thirds mainly reflects trajectory of control, not inherent pregnancy risk.
- Prevention
Assess and document control at the first prenatal visit and every visit after, using the same symptom-frequency, nighttime-awakening, SABA-use, and activity-limitation criteria as the general…
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