Stomach bug (norovirus) during pregnancy

By trimester

Weeks 1–13

1st trimester

Dehydration from vomiting and diarrhea can be harder to tell apart from morning sickness this early, so mention new diarrhea, fever, or vomiting that doesn't match your usual nausea pattern to your provider.

Weeks 14–27

2nd trimester

Staying hydrated matters at any stage. A short viral bug is usually not a concern for the pregnancy itself, but vomiting and diarrhea that stick around beyond a few days is still worth a call.

Weeks 28–birth

3rd trimester

Dehydration and cramping close to your due date can be harder to tell apart from labor, so let your provider know if diarrhea or vomiting shows up along with regular contractions.

What does the evidence show for stomach bug?

• Norovirus has a short incubation period, typically 24 to 48 hours from exposure to symptoms, and is highly contagious: as few as 10 viral particles can cause infection, making person-to-person spread the most common route in households and other close-contact settings. 1
• Viral gastroenteritis, often called stomach flu even though flu viruses don't cause it, typically brings watery diarrhea, abdominal cramping, nausea or vomiting, and sometimes fever, with norovirus symptoms usually starting 12 to 48 hours after exposure and lasting 1 to 3 days. 2
• Pregnancy is explicitly named among the circumstances where a patient with viral gastroenteritis may benefit from hospital observation or admission, alongside signs of dehydration, intractable vomiting, severe electrolyte disturbances, or severe abdominal pain. 3
• Viral gastroenteritis spreads through the fecal-oral route as well as contact with contaminated surfaces, vomit, and possibly airborne particles, and norovirus's unusual resistance to routine cleaning helps explain why it moves so easily through households and shared spaces. 4
• Viral gastroenteritis spreads through contact with small particles of an infected person's stool or vomit, which is why thorough handwashing and surface cleaning matter for protecting other household members. 5

When should I call my provider about stomach bug?

Dehydration is the most common complication of a stomach bug, and pregnancy is one of the situations where a clinician may want to see you for observation, especially with signs of dehydration, vomiting that won't stop, severe abdominal pain, a high fever, or bloody diarrhea. Symptoms lasting more than about three days, or any blood in vomit or stool, go beyond a typical short-lived stomach bug and are worth same-day medical attention. Trust your read on your own body. If something feels off beyond the list above, please consult your healthcare provider rather than waiting it out.