A fever during pregnancy can bring up a lot of questions, and a fever is absolutely worth paying attention to during pregnancy.
In this article, you’ll learn what counts as a fever during pregnancy, why timing matters, what research says about fever and fetal development, what we currently know about acetaminophen use during pregnancy, and when to contact your healthcare provider.
What Counts as a Fever During Pregnancy?
Pregnancy can make you feel warmer than usual. Progesterone raises baseline body temperature slightly, while increased blood volume and metabolic demand can make feeling flushed or overheated more common.
Feeling hot, however, is not the same thing as having a fever. A temperature of 100.4°F (38°C) or higher is generally considered a fever. The CDC also includes a temperature at or above 100.4°F among its urgent maternal warning signs during pregnancy (1).
For the most useful reading, check your temperature with a thermometer rather than relying on how warm you feel. If you have recently exercised, taken a hot shower, or had a very hot or cold drink, give your body some time before checking again.
To learn more about fevers, read this article: Fevers 101: Benefits, Home Care Strategies, & When to Medicate
Why Fever During Pregnancy Deserves Attention
When fever occurs during pregnancy, there are really two things to consider:
The elevated body temperature itself and the illness causing it.
These concerns are not necessarily the same throughout pregnancy. The first trimester is the most sensitive developmental period because the neural tube closes and major organs begin forming during these early weeks.
Some research has found associations between significant maternal fever or hyperthermia early in pregnancy and certain birth defects, particularly neural tube defects. Associations with some heart defects and oral clefts have also been reported (2).
That does not mean that having a fever means something will be wrong with your baby.
In fact, another large prospective cohort study found no overall increase in congenital malformations among babies whose mothers reported fever during the first trimester (3).
Taken together, the evidence suggests that the clearest concern is with certain specific developmental outcomes rather than a broad increase in birth defects after any fever.
Fever During the First Trimester
The first trimester is the period when a true fever deserves the most attention from a developmental standpoint.
One large study found that fever around conception was associated with approximately twice the odds of neural tube defects. Interestingly, that association was substantially lower among women consuming at least 400 micrograms of folate per day compared with women who had lower folate intake (4).
To be clear, this does not mean folate eliminates the potential effects of maternal fever. It does reinforce the importance of adequate folic acid intake before conception and during early pregnancy (5).
If you develop a measured fever during the first trimester, contact your prenatal healthcare provider.
What About Fever in the Second and Third Trimesters?
Later in pregnancy, the period when fever is most strongly associated with structural birth defects has largely passed.
At that point, the cause of the fever often becomes the bigger concern.
Influenza, kidney infections, COVID-19, foodborne illnesses, and other infections can become more significant during pregnancy and may require treatment even when the temperature itself is relatively modest.
A temperature of 100.4°F (38°C) or higher during pregnancy is still worth contacting your healthcare provider about, regardless of trimester (1).
Common Causes of Fever During Pregnancy
Many common infections can cause fever during pregnancy, but a few deserve particular attention.
Influenza
Pregnant women have a higher risk of developing serious complications from influenza.
The CDC recommends prompt antiviral treatment for suspected or confirmed influenza during pregnancy. Oral oseltamivir is the preferred treatment because it has the most pregnancy safety data, and treatment works best when started early (6).
Fever accompanied by body aches, chills, cough, sore throat, or other flu-like symptoms is worth a prompt call to your healthcare provider.
Urinary Tract and Kidney Infections
Urinary tract infections are common during pregnancy and can sometimes progress to a kidney infection, or pyelonephritis.
Fever combined with back or flank pain, painful urination, urinary urgency, nausea, or vomiting should be evaluated.
Pyelonephritis during pregnancy can lead to complications including sepsis and preterm labor and generally requires medical treatment (7).
Foodborne Illness
Pregnancy increases susceptibility to serious illness from Listeria monocytogenes.
Fever, muscle aches, fatigue, or digestive symptoms after eating a potentially high-risk food should be discussed with your healthcare provider (8).
Should You Bring a Fever Down During Pregnancy?
A real fever during pregnancy should not be ignored. This is especially true during the first trimester, when elevated maternal temperature overlaps with critical stages of fetal development.
Supportive measures can help while you contact your healthcare provider and determine what is causing the fever.
- Stay hydrated. Fever increases fluid losses, and pregnancy already increases fluid needs.
- Dress lightly. Heavy blankets can trap heat and make you more uncomfortable.
- Try lukewarm water. A lukewarm shower, sponge bath, or cool compress may help. Avoid very cold water or ice baths, which can trigger shivering and generate additional heat.
- Avoid extra heat. Skip hot tubs, saunas, very hot baths, and other sources of overheating while you have a fever.
- Track your temperature. Write down your readings and when you took them so you can tell whether the fever is rising, falling, persisting, or returning.
Reducing the temperature is only one part of the picture. Finding out why the fever is happening is equally important.
What About Acetaminophen During Pregnancy?
Acetaminophen (also called paracetamol and commonly sold under the brand name Tylenol) is the medication most commonly recommended for reducing fever during pregnancy.
You may have seen concerns about prenatal acetaminophen exposure and later autism or ADHD.
Some observational studies have reported associations, but these studies are difficult to interpret because people usually take acetaminophen for a reason (including fever, infection, inflammation, or pain) and those underlying conditions can influence outcomes too.
More recent sibling-controlled studies, which better account for shared genetic and family factors, have not found an increased risk of autism, ADHD, or intellectual disability associated with prenatal acetaminophen exposure (9,10).
The FDA currently states that there may be a possible association and updated labeling in 2025 (11). ACOG, however, maintains that current evidence does not establish that acetaminophen causes neurodevelopmental disorders and continues to recommend it when treatment for fever or pain is medically indicated during pregnancy (12).
This matters in the context of fever because leaving a fever untreated is not necessarily a risk-free choice either. Maternal fever itself has been associated with certain pregnancy and neurodevelopmental outcomes, particularly when it occurs early in pregnancy (2,4,13).
Medication decisions during pregnancy should therefore consider both the reason for treatment and the potential risks of leaving that condition untreated.
What About Ibuprofen, Naproxen, and Aspirin During Pregnancy?
NSAIDs such as ibuprofen (Advil, Motrin) and naproxen (Aleve) require particular caution during pregnancy.
The FDA recommends avoiding NSAIDs at 20 weeks of pregnancy or later unless specifically advised by a healthcare professional because they can cause fetal kidney problems and low amniotic fluid. Later in pregnancy, NSAIDs can also affect the fetal heart (14).
Aspirin should not be used as a routine fever reducer during pregnancy unless specifically recommended by a healthcare provider.
This is different from low-dose aspirin, which may be intentionally prescribed during pregnancy for reasons such as reducing the risk of preeclampsia.
To learn more, read this article: Herbs for Pain Relief: Safe Options in Pregnancy & Lactation
What About Natural Fever Remedies During Pregnancy?
Natural does not automatically always mean safe during pregnancy.
Many herbs traditionally used for fever or immune support have traditionally been used by herbalists during pregnancy. It is important to work with trusted providers and trusted, third party tested products when considering natural medicine during pregnancy.
To learn more, read this article: 10 Homeopathic Remedies for Treating Fevers
When to Call Your Healthcare Provider About Fever in Pregnancy
If you are pregnant, contact your prenatal healthcare provider if your temperature reaches 100.4°F (38°C) or higher, particularly if it persists, keeps returning, or occurs with other symptoms.
It helps to have the following information ready:
- Your actual temperature readings
- How long the fever has lasted
- How far along you are
- Any medications you have taken
- Other symptoms such as cough, urinary symptoms, rash, vomiting, pain, or diarrhea
- Any recent illness exposures, travel, or potentially high-risk foods
When to Seek Urgent Care for Fever in Pregnancy
Seek prompt medical evaluation if fever occurs along with:
- Trouble breathing or chest pain
- Confusion or fainting
- Severe or worsening headache
- Severe vomiting or signs of dehydration
- Severe abdominal pain
- Vaginal bleeding
- Leaking fluid
- Contractions
- Decreased fetal movement
If something feels seriously wrong, you do not need to wait for your temperature to reach a particular number before seeking care (your gut feeling matters – trust it!).
Preventing Fever-Causing Illness During Pregnancy
Not every infection can be prevented, but a few steps can lower your risk.
Practice food safety. Avoid unpasteurized foods and follow pregnancy-specific guidance for foods associated with a higher risk of Listeria.
To learn more, read this article: Dr. Green Mom’s Guide to Healthy Eating During Pregnancy
Wash your hands regularly and avoid close contact with people who are actively sick when possible.
Support your overall immune health by prioritizing adequate sleep, regular meals with nutrient-dense foods, hydration, and meeting your pregnancy nutrient needs.
Summary
A fever during pregnancy deserves attention, but in the majority of cases it does not cause long term harm.
The first trimester is the period when elevated maternal temperature raises the most concern because early fetal development is taking place. Later in pregnancy, the illness causing the fever often becomes the bigger issue.
If you develop a temperature of 100.4°F (38°C) or higher, contact your prenatal healthcare provider. Stay hydrated, avoid additional sources of heat, track your temperature, and pay attention to symptoms that may point toward the underlying cause.
When medication is needed, acetaminophen remains the fever reducer most commonly recommended during pregnancy.
Most importantly, treatment decisions should consider both sides of the equation: the medication being used and the fever or illness it is being used to treat.
References
- Centers for Disease Control and Prevention. (2024, May 15). Urgent maternal warning signs and symptoms. https://www.cdc.gov/hearher/maternal-warning-signs/index.html
- Graham, J. M., Jr. (2020). Update on the gestational effects of maternal hyperthermia. Birth Defects Research, 112(12), 943–952. https://doi.org/10.1002/bdr2.1696
- Sass, L., Urhoj, S. K., Kjærgaard, J., Dreier, J. W., Strandberg-Larsen, K., & Nybo Andersen, A.-M. (2017). Fever in pregnancy and the risk of congenital malformations: A cohort study. BMC Pregnancy and Childbirth, 17(1), 413. https://doi.org/10.1186/s12884-017-1585-0
- Kerr, S. M., Parker, S. E., Mitchell, A. A., Tinker, S. C., & Werler, M. M. (2017). Periconceptional maternal fever, folic acid intake, and the risk for neural tube defects. Annals of Epidemiology, 27(12), 777–782.e1. https://doi.org/10.1016/j.annepidem.2017.10.010
- Centers for Disease Control and Prevention. (2026). About folic acid. https://www.cdc.gov/folic-acid/about/index.html
- Centers for Disease Control and Prevention. (2025). Recommendations for obstetric health care providers related to use of antiviral medications for the treatment and prevention of influenza. https://www.cdc.gov/flu/hcp/antivirals/treatment_obstetric.html
- American College of Obstetricians and Gynecologists. (2023, August). Urinary tract infections in pregnant individuals. https://www.acog.org/clinical/clinical-guidance/clinical-consensus/articles/2023/08/urinary-tract-infections-in-pregnant-individuals
- Centers for Disease Control and Prevention. (2025, January 31). Safer food choices for pregnant women. https://www.cdc.gov/food-safety/foods/pregnant-women.html
- Ahlqvist, V. H., Sjöqvist, H., Dalman, C., Karlsson, H., Stephansson, O., Johansson, S., Magnusson, C., Gardner, R. M., & Lee, B. K. (2024). Acetaminophen use during pregnancy and children’s risk of autism, ADHD, and intellectual disability. JAMA, 331(14), 1205–1214. https://doi.org/10.1001/jama.2024.3172
- D’Antonio, F., Flacco, M. E., Della Valle, L., Prasad, S., Manzoli, L., Samara, A., & Khalil, A. (2026). Prenatal paracetamol exposure and child neurodevelopment: A systematic review and meta-analysis. The Lancet Obstetrics, Gynaecology, & Women’s Health, 2(3), e190–e198. https://doi.org/10.1016/S3050-5038(25)00211-0
- U.S. Food and Drug Administration. (2025, September 22). FDA responds to evidence of possible association between autism and acetaminophen use during pregnancy. https://www.fda.gov/news-events/press-announcements/fda-responds-evidence-possible-association-between-autism-and-acetaminophen-use-during-pregnancy
- American College of Obstetricians and Gynecologists. (2025, September). Acetaminophen use in pregnancy and neurodevelopmental outcomes. https://www.acog.org/clinical/clinical-guidance/practice-advisory/articles/2025/09/acetaminophen-use-in-pregnancy-and-neurodevelopmental-outcomes
- Antoun, S., Ellul, P., Peyre, H., Rosenzwajg, M., Gressens, P., Klatzmann, D., & Delorme, R. (2021). Fever during pregnancy as a risk factor for neurodevelopmental disorders: Results from a systematic review and meta-analysis. Molecular Autism, 12, 60. https://doi.org/10.1186/s13229-021-00464-4
- U.S. Food and Drug Administration. (2022, September 1). FDA recommends avoiding use of NSAIDs in pregnancy at 20 weeks or later because they can result in low amniotic fluid. https://www.fda.gov/drugs/fda-drug-safety-podcasts/fda-recommends-avoiding-use-nsaids-pregnancy-20-weeks-or-later-because-they-can-result-low-amniotic
