Fever during pregnancy

By trimester

Weeks 1–13

1st trimester

The first trimester, especially before week 6, is the window where a high fever has been linked to a small rise in neural tube defect risk. This is when bringing a fever down quickly matters most, and acetaminophen at the lowest effective dose is generally the safest way to do it. Call your provider if your temperature is above 101°F or isn't coming down.

Weeks 14–27

2nd trimester

Morning sickness often eases up by now, but a fever still deserves quick attention. Acetaminophen remains the go-to option, and starting around week 20, it's smart to set ibuprofen aside unless your provider says otherwise. A fever alongside other symptoms, like a cough or sore throat, is worth a same-day call.

Weeks 28–birth

3rd trimester

Your body is already working harder late in pregnancy, so a fever can feel more draining and is worth a prompt call to your provider, especially close to your due date. Keep leaning on acetaminophen instead of ibuprofen, and mention any fever to your care team even if it settles on its own.

What does the evidence show for fever?

• Bringing a high fever down early in pregnancy matters, since temperatures above 101°F before week 6 have been linked to a small rise in neural tube defect risk. 1
• A high temperature in early pregnancy has been linked to nearly double the odds of a neural tube defect across pooled research, one reason first-trimester fevers get taken seriously. 2
• Acetaminophen is still the fever and pain reliever most healthcare providers reach for first during pregnancy, used at the lowest dose that works. 3
• Ibuprofen is best set aside for fever after 20 weeks of pregnancy unless your provider says it's fine, which is another reason acetaminophen stays the default choice. 1
• A fever alongside flu-like symptoms during pregnancy is worth a same-day call to your provider, both to check what's safe for the fever itself and to see whether the illness behind it needs attention too. 4

When should I call my provider about fever?

A fever that lingers for more than a day rather than breaking quickly is taken more seriously than a brief spike, since how long a high temperature lasts factors into the concern in early pregnancy. A fever alongside real trouble breathing or a cough that keeps getting worse is a different situation than fever alone, since flu during pregnancy can turn into serious breathing problems that need same-day, hospital-level evaluation rather than home monitoring. 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.