Hives during pregnancy

By trimester

Weeks 1–13

1st trimester

New hives in the first trimester may follow an infection, food, medicine, insect sting, heat, cold, or pressure, but many episodes have no clear trigger. Record recent exposures and how long each spot lasts rather than assuming pregnancy itself is the cause.

Weeks 14–27

2nd trimester

Chronic urticaria does not follow one pregnancy pattern. In the PREG-CU questionnaire study, some participants improved, some worsened, and others had no change, so a personal flare plan is more useful than a trimester prediction.

Weeks 28–birth

3rd trimester

Late-pregnancy itching needs a close look at the skin. Moving wheals fit urticaria, abdominal plaques arising in stretch marks suggest polymorphic eruption of pregnancy, and severe palm or sole itching without a primary rash raises concern for cholestasis.

What does the evidence show for hives?

• A typical urticaria wheal is itchy, pink or red, sometimes pale in the center, and disappears from one location within 24 hours without bruising or pigmentation; a fixed, painful, or bruising lesion needs another explanation. 1
• In the international PREG-CU questionnaire study of 288 participants with chronic urticaria, 51.1% reported improvement during pregnancy, 28.9% worsening, and 20.0% no change; these retrospective reports do not predict an individual course. 2
• A pregnancy-focused review identifies cetirizine and loratadine as the best-studied second-generation antihistamines for chronic urticaria, while emphasizing that pregnancy evidence is limited and medication choice belongs with a clinician. 3
• Pregnancy-specific rashes can resemble hives: polymorphic eruption usually starts in abdominal stretch marks late in pregnancy, while intrahepatic cholestasis usually causes intense itching without primary skin lesions, often on the palms and soles. 4
• Hives with deeper swelling can involve the lips, eyes, hands, feet, or throat; breathing difficulty, wheezing, abnormal breathing sounds, or fainting requires emergency care because throat swelling can obstruct the airway. 5

When should I call my provider about hives?

Call 911 for hives with trouble breathing, wheezing, abnormal breathing sounds, fainting, or swelling of the tongue or throat. Seek urgent same-day care for severe new facial swelling, fever with a widespread rash, blistering, or severe palm and sole itching without primary wheals. Painful spots that remain in one place longer than 24 hours, bruise, or occur with joint pain need prompt assessment for a condition other than routine urticaria. None of these lists replace your own judgment: if this symptom worries you, that on its own is enough reason to check in with your healthcare provider.