The average body temperature is usually around 98.6 F (37 C). A fever happens when your body reaches a higher temperature than the normal range. A fever may be a sign of infection, so it’s important to get it checked out.
Can having a fever hurt my baby?
Having a fever during pregnancy—especially during your 1st trimester—may cause problems for your baby.
People who had a fever just before or during early pregnancy were more than twice as likely to have a baby with a neural tube defect (NTD) than those who didn’t have a fever. NTDs are birth defects of the brain, spine and spinal cord. According to the CDC, getting 400 micrograms of folic acid every day while pregnant can reduce the risk of neural tube defects, even if you have a fever.
A temperature higher than 103 F (39.4 C) during the 1st trimester also may increase the risk of:
- Autism spectrum disorder (more research is needed in this area)
- Cleft lip and cleft palate
- Congenital heart defects
- Miscarriage
Having a fever later in your pregnancy may increase your risk of preterm labor.
How do I know if I have a fever?
There are five places on your body that you can take your temperature:
- Armpit
- Ear
- Forehead
- Mouth
- Rectum
In general, there are two types of thermometers. Touch thermometers (also called contact thermometers) must touch your body to measure your temperature. Remote (also called no-contact thermometers) measure body temperature without touching your skin.
Your temperature will fluctuate throughout the day, and a rise of a degree or two is normal. For adults, your temperature is considered a fever if:
- It’s higher than 100 F (37.8 C) when taken by mouth
- It’s higher than 100.4 F (38 C) when taken by forehead, ear or rectally
- It’s higher than 99 F (37.2 C) when taken by armpit
Why do I have a fever?
Common reasons for a fever while pregnant include:
- Ear infection
- Food poisoning
- Genital infections
- Pneumonia
- Respiratory viruses, such as colds, flu and coronavirus disease (COVID-19)
- Stomach virus
- Urinary tract infection (including kidney infection)
Some physical activities can raise your body temperature, too. This includes Bikram yoga (also called hot yoga) or exercising outside on hot, humid days. Some studies suggest that spending too much time in a sauna or hot tub may make your body temperature too high and increase your risk of having a baby with birth defects. To be safe, it’s best to skip these types of activities during pregnancy.
What should I do if I have a fever?
Call your provider if you have a fever. Most pregnant people can take acetaminophen (Tylenol®) to lower their temperature. Cooling blankets also may help. If the cause of the fever is a bacterial infection, you may be prescribed an antibiotic. You should not take aspirin or ibuprofen to lower your fever while pregnant. It’s OK to take low-dose aspirin during pregnancy if your provider recommends it for preeclampsia.
If you have a fever while pregnant, talk to your provider as soon as possible, especially if you have:
- Severe thirst
- Dark urine (pee) or are peeing less
- Vaginal discharge with a bad smell
- Dizziness
- Severe cramps
- Trouble breathing
Also, call your provider if the baby doesn’t seem to be moving as much.
The best way to avoid getting a fever is to take steps not to get sick. Be sure to wash your hands frequently or use hand sanitizer, stay away from sick people, eat healthy foods and get enough sleep.