Is Singulair (Montelukast) safe in pregnancy?

Common uses

Asthma, allergic rhinitis

How Singulair (Montelukast) works and why pregnancy changes the math

Singulair (Montelukast) is a leukotriene receptor antagonist — it blocks one of the inflammatory pathways that drives asthma and some types of allergic rhinitis. It is taken daily as a controller medication rather than used for acute symptom relief.

The pregnancy data on this drug class is reassuring, and most obstetric practices are comfortable continuing it for anyone whose asthma was well-controlled on it before pregnancy. Switching maintenance asthma medications mid-pregnancy carries its own risk of destabilization, so continuity is usually preferred over change. The bigger pregnancy concern is undertreated asthma, not the medication itself.

How Singulair (Montelukast) risk changes by trimester

The clinical reasoning behind the verdict

Reassuring pregnancy data.

Dosing and what to do if symptoms keep going

Asthma control medications follow standard dosing in pregnancy in most cases. The principle is that maintaining control is the goal — overcorrecting toward less medication because of pregnancy anxiety often results in worse control and worse outcomes. Maintenance medications should generally continue at the same dose unless your pulmonary or obstetric provider directs otherwise.

If asthma symptoms are worsening in pregnancy — which can happen because of hormonal effects on airways — that is a call to your provider for adjustment, not a sign to stop medications. An asthma flare in pregnancy that goes untreated can become an emergency quickly. Use your rescue inhaler as needed and follow up with your provider about whether maintenance therapy needs strengthening.

Safer alternatives and how to choose between them

Continue if previously on it for asthma.

The right alternative depends on what Singulair (Montelukast) was being used to treat. For mild symptoms, non-medication approaches often work — saline rinses for congestion, ice for swelling, heat for muscle pain, rest for fatigue. For ongoing conditions, pregnancy-safe medications usually exist and are best identified with your provider's input.

The trap to avoid is stopping a needed medication abruptly without a replacement plan, especially for chronic conditions like hypertension, diabetes, depression, or autoimmune disease. Untreated maternal conditions usually carry pregnancy risks of their own, sometimes larger than the risks of the medication being avoided. A pregnancy-aware substitute usually beats stopping treatment.

What recent research has been saying about Singulair (Montelukast)

The literature on Singulair (Montelukast) in pregnancy continues to evolve as more population-level data accumulates and as researchers control more carefully for confounding factors. The pregnancy-specific evidence base for any given medication is rarely as deep as the general adult evidence base, so cautious clinical interpretation and individualized provider conversation remain the right approach as guidance updates.

Sources and further reading

ACOG Asthma 2024