Is Zyrtec (cetirizine) safe to use during pregnancy?

Is Zyrtec (Cetirizine) Safe During Pregnancy?

Cetirizine is generally considered safe for use during pregnancy, particularly when antihistamine therapy is necessary for maternal health, though it should ideally be avoided in the first trimester when possible. 1, 2

Evidence-Based Safety Profile

FDA and Guideline Classification

• Cetirizine is classified as an FDA Pregnancy Category B drug, meaning animal studies have not demonstrated fetal risk, though well-controlled human studies are not available to completely exclude harmful effects 1
• The FDA drug label for cetirizine states that pregnant women should "ask a health professional before use" 2
• British guidelines note that while it's best to avoid all antihistamines in pregnancy, especially during the first trimester, none has been shown to be teratogenic in humans 1

Clinical Evidence Supporting Safety

• Cetirizine and loratadine are the most well-studied second-generation antihistamines in pregnancy and are generally considered safe 3, 4
• A large Danish registry study (2020) comparing fexofenadine to cetirizine during pregnancy found no increased risk of major birth defects, spontaneous abortion, preterm birth, small for gestational age, or stillbirth with either antihistamine 5
• Cetirizine is often chosen as a first-line antihistamine during pregnancy due to its extensive safety data 1, 4

Practical Prescribing Approach

When to Use Cetirizine

• Cetirizine should be used when maternal allergic disease requires treatment, as uncontrolled allergic conditions can negatively impact maternal and fetal health 1, 3
• It is preferred over first-generation antihistamines (like diphenhydramine) which have sedating effects and some association with congenital defects 1
• Use the lowest effective dose to minimize any theoretical fetal exposure 1

Timing Considerations

• If possible, avoid initiating any antihistamine therapy during the first trimester when organogenesis occurs and teratogenic risk is theoretically highest 1
• However, if the patient is already taking cetirizine and becomes pregnant, continuation is generally acceptable as the benefit of controlled maternal disease outweighs theoretical risks 1, 3
• Cetirizine can be used throughout the second and third trimesters with greater confidence 1

Special Populations

• In patients with renal impairment, the cetirizine dose should be halved 1
• Cetirizine should be avoided in severe renal impairment (creatinine clearance <10 mL/min) 1

Important Caveats

Breastfeeding Considerations

• The FDA drug label states that cetirizine is "not recommended" during breastfeeding 2
• This recommendation should be balanced against maternal need for symptom control

Alternative Approaches

• Conservative measures should be tried first: saline nasal irrigation, positioning, exercise, and nasal valve dilators are completely safe in pregnancy 3
• Intranasal corticosteroids (particularly budesonide) may be preferred for allergic rhinitis as they have strong safety data and provide effective local treatment with minimal systemic absorption 3, 4

What to Avoid

• Hydroxyzine is specifically contraindicated in early pregnancy and should not be used 1
• First-generation antihistamines like diphenhydramine have been associated with cleft palate and should be avoided when safer alternatives exist 1

The key principle is that controlled maternal allergic disease is safer for the fetus than uncontrolled disease, making cetirizine an acceptable choice when antihistamine therapy is medically necessary during pregnancy. 1, 3