Sinus infections during pregnancy (rhinosinusitis)

By trimester

Weeks 1–13

1st trimester

Rising pregnancy hormones increase blood flow and swelling in your nasal lining from early on, which can mimic or worsen congestion even without an infection. If a true sinus infection develops now, first-line care is the same as at any stage: saline rinses, hydration, rest, and acetaminophen for pain or fever. Some medications get extra scrutiny in this window, so confirm any antibiotic with your prescriber instead of reaching for leftover medication from a past illness.

Weeks 14–27

2nd trimester

Second-trimester sinus infections follow the same pattern as the rest of pregnancy: most congestion is viral and gets better with supportive care within one to two weeks. If a clinician confirms a bacterial infection, pregnancy-compatible antibiotics like amoxicillin are commonly used, and this window is generally considered lower-concern for a short antibiotic course when one is truly needed.

Weeks 28–birth

3rd trimester

Sinus symptoms tend to feel worse in the third trimester than the second, according to research following pregnant women, so don't assume worsening congestion late in pregnancy is just ordinary discomfort. Reduced lung capacity and increased nasal blood flow late in pregnancy can make breathing through a blocked nose harder, and facial pain plus fever are reasons to call your provider rather than wait it out. Your obstetric team can also time any antibiotic around your delivery date if one is prescribed close to your due date.

What does the evidence show for sinus infections?

• Guidance to reserve pregnancy-safe antibiotics for acute or flare-up sinus infections is based on expert consensus, since a 2016 review and expert panel found no high-quality clinical trials specifically testing sinusitis care during pregnancy. 1
• Bacterial cultures came back positive far more often in pregnant patients with acute sinusitis than in non-pregnant patients (78.9% versus 54.9%), with Streptococcus pneumoniae the leading cause and an even higher share of cases in the third trimester. 2
• Sinus-related quality of life was measurably worse in the third trimester than the second among pregnant women followed for symptoms, which supports paying closer attention to sinus symptoms as pregnancy progresses. 3
• Most studies of amoxicillin and amoxicillin-clavulanic acid taken in the first trimester have not found an increased chance of birth defects, preterm delivery, or low birth weight, for the antibiotics used once a bacterial sinus infection is confirmed. 4
• For the facial pain, pressure, or fever that come with a sinus infection, acetaminophen at the recommended dose remains the first-choice pain reliever and fever reducer for most healthcare providers throughout pregnancy. 5
• A sinus infection can rarely spread toward the eye socket, causing eyelid swelling or redness, pain with eye movement, double vision, or vision loss, sometimes with fever, a pattern known as orbital cellulitis that needs urgent evaluation rather than home care. 6

When should I call my provider about sinus infections?

Most sinus infections stay confined to facial pressure and congestion, but swelling or redness around one eye, pain when you move your eye, or new double vision or blurred vision can mean the infection is spreading toward the eye socket, a rare but urgent complication that needs same-day care. A fever alongside that kind of eye swelling raises the urgency further. Facial pain that is severe, one-sided, or keeps building for more than a few days, or congestion that improves and then suddenly worsens again with a new fever, also points toward a bacterial infection that has moved beyond a simple cold. Whatever the pattern, any symptom that feels beyond your usual range is a reason to call: obstetric teams expect these questions and would rather hear early than late.