Fever During Pregnancy: Safe Treatment, Symptoms, and When to Call the Doctor

If you're dealing with a fever during pregnancy, the two big questions are simple: How worried should I be, and what can I do right now? Here’s the short answer: most low-grade fevers come from common infections and are manageable at home, but you shouldn’t ignore persistent or high temperatures. You’ll get clear thresholds, safe steps to bring your temp down, and a decision guide for when to call your OB, head to urgent care, or go straight to the ER.

Expect straight talk here. I’ll show you what counts as a fever in pregnancy, how to manage it safely without guessing, the specific red flags that change the plan, and how to lower your risk the rest of the way. Guidance reflects current U.S. recommendations as of 2025 from groups like ACOG and CDC.

TL;DR: What to Expect and What to Do

• Fever is 100.4°F (38°C) or higher. 102°F (38.9°C) or higher needs urgent attention.
• Acetaminophen (Tylenol) is the go-to in pregnancy: 650 mg every 4-6 hours or 1,000 mg every 6-8 hours; max 3,000 mg in 24 hours unless your clinician says otherwise.
• Avoid ibuprofen, naproxen, and other NSAIDs-especially after 20 weeks-unless your clinician specifically tells you to take them.
• Call your OB now if: fever lasts over 24 hours, you have painful urination/flank pain, shortness of breath, severe sore throat with dehydration, a new rash, stiff neck, severe headache, contractions, decreased fetal movement, or foul discharge.
• Go to the ER if temp is 102°F+ (38.9°C), you can’t keep fluids down, you’re confused or very drowsy, you have chest pain or trouble breathing, or severe belly/flank pain.

What Counts as a Fever in Pregnancy and What It Means

A true fever is 100.4°F (38°C) or higher. That number matters because fever is your body’s response to infection, inflammation, or (less often) a non-infectious issue like heat illness. Pregnancy changes your immune and cardiovascular systems, so some infections hit harder. The goal isn’t to chase a perfect number; it’s to treat the cause, bring the temperature down, and watch for red flags.

Why 102°F (38.9°C) is a tipping point: higher fevers stress you and the baby more. Early in pregnancy, untreated high fevers have been tied to certain birth defects; later in pregnancy, infections linked with fever can raise the risk of preterm labor. ACOG and CDC emphasize prompt treatment and hydration. The fix isn’t fancy-meds, cooling, and clinical follow-up when needed.

What fever is not: heat from overexertion on a hot day without an actual infection is heat exhaustion/heat stroke, not a classic immune-driven fever. That still needs fast cooling and medical attention if severe.

Step-by-Step: Safe Home Treatment and What to Avoid

Use this when your temperature is 100.4-101.9°F (38-38.8°C) and you don’t have red flags.

1. Confirm the fever right: use a reliable digital oral thermometer. Wait 15 minutes after hot/cold drinks before measuring. Take two readings, 5 minutes apart, and jot them down with the time and symptoms.
2. Hydrate on a schedule: drink small amounts often. Aim for a half cup every 15-20 minutes if you feel queasy. Clear, pale urine every 3-4 hours is your target. Add an oral rehydration solution or broth for electrolytes if you’re sweating or vomiting.
3. Take acetaminophen correctly: 650 mg every 4-6 hours or 1,000 mg every 6-8 hours, max 3,000 mg in 24 hours. Check labels-many “cold and flu” combos also contain acetaminophen, so you don’t double up. If you have liver disease or take other meds that affect the liver, call your clinician first.
4. Cool the smart way: light clothing, lukewarm shower or sponge bath, a fan, room at 68-72°F (20-22°C). Skip ice baths and alcohol rubs-they don’t help and can be risky.
5. Rest, but move a little: short walks at home keep blood moving and clear your head. Don’t overexert. Sleep when you can.
6. Watch the clock and your notes: if your fever doesn’t drop within 60-90 minutes after acetaminophen, or it returns and lasts beyond 24 hours, call your OB’s office.

What to avoid:

• NSAIDs (ibuprofen, naproxen) unless your clinician says to use them. The FDA warns of problems like low amniotic fluid after 20 weeks and ductus arteriosus issues later in pregnancy.
• Aspirin unless your clinician prescribed low-dose aspirin for a specific reason (like preeclampsia prevention). That’s a separate use case.
• Decongestants with pseudoephedrine or phenylephrine in the first trimester unless cleared by your clinician. Always check labels.
• Herbal “fever teas” and supplements with sketchy ingredients. Natural doesn’t always mean safe in pregnancy.
• Overheating: hot tubs, saunas, or long hot baths when you already have a fever.

When to Call, Go to Urgent Care, or Head to the ER

Use this quick decision guide.

• Call your OB today if: your fever lasts more than 24 hours; you have a severe sore throat and can’t swallow fluids; ear pain or drainage; sinus pain with thick discharge and fever over 24-48 hours; vaginal discharge that’s foul-smelling; contractions, belly pain, or decreased fetal movement; you recently ate high-risk foods (unheated deli meat, unpasteurized dairy) and developed fever or GI symptoms.
• Go to urgent care today if: your doctor can’t see you promptly and you have fever plus painful urination, flank pain, bad sinus/ear symptoms, or suspected strep throat/flu/COVID. Ask for pregnancy-safe testing and treatments.
• Go to the ER now if: temperature hits 102°F (38.9°C) or higher; you can’t keep fluids down; you’re confused, very drowsy, or fainting; you have trouble breathing or chest pain; you have severe belly or back pain; you have a severe headache with a stiff neck or a new widespread rash; you just returned from malaria or dengue areas and have a fever.

Why this approach works: it splits “can monitor at home” from “needs testing and possibly antibiotics” from “time-critical emergency.” It mirrors how clinicians triage pregnant patients.

Causes, Risks by Trimester, Prevention, and Your Next Steps

Common causes in pregnancy:

• Viral respiratory infections: cold viruses, influenza, COVID-19. Pregnancy raises the risk of severe flu and COVID, which is why vaccines are pushed hard.
• Urinary tract infection: very common in pregnancy; can progress to kidney infection with high fevers and back pain. Needs antibiotics promptly.
• Gastrointestinal infections: norovirus, foodborne bugs. Listeria risk is about 10 times higher during pregnancy per CDC; think fever, muscle aches, and GI upset after risky foods.
• Reproductive tract infections: bacterial vaginosis or other infections can present with discharge and fever; later in pregnancy, chorioamnionitis (infection of the membranes) can cause fever and needs urgent care.
• Other infections: strep throat, sinusitis, ear infections; less commonly, parvovirus B19, CMV, or toxoplasmosis depending on exposures. Fever after travel can point to malaria or dengue.

What this means by trimester:

• First trimester (0-13 weeks): untreated high fevers have been linked in observational studies to certain birth defects (e.g., neural tube defects). This is part of why folic acid and prompt fever treatment matter. The key is fast control and clinician guidance, not panic.
• Second trimester (14-27 weeks): UTIs and respiratory infections can still spike fevers. NSAIDs become especially problematic after 20 weeks (FDA warning) due to risks to the fetus and amniotic fluid. Stick with acetaminophen unless told otherwise.
• Third trimester (28+ weeks): fever plus contractions or fluid leakage needs urgent evaluation. Late-pregnancy infections can trigger preterm labor. Also ask about seasonal RSV, flu, and updated COVID vaccination to protect you and the newborn.

Prevention that actually helps (2025, U.S.):

• Vaccines during pregnancy: inactivated flu vaccine any trimester each flu season; current COVID-19 vaccine per CDC timing; maternal RSV vaccine typically 32-36 weeks during RSV season to protect newborns. ACOG and CDC back these for safety and benefit.
• Food safety: avoid unheated deli meats, raw sprouts, unpasteurized dairy/juices, undercooked eggs and meats. Reheat deli meats until steaming. Wash produce well. Keep fridge at or below 40°F (4°C).
• UTI prevention: pee after sex, drink water through the day, don’t delay bathroom breaks. Tell your clinician if you’ve had recurrent UTIs-they may screen more often.
• Hygiene and sick contacts: wash hands often, use masks around sick people if that’s your comfort zone, and don’t share drinks.
• Heat safety: on hot Seattle days or travel, limit time in heat, hydrate, and cool off early. If you stop sweating or feel dizzy, that’s a problem-cool down and seek help if not improving.

Real-world examples to anchor your decisions:

• 18 weeks, 100.8°F with runny nose and cough, still drinking fluids: take acetaminophen, hydrate, cool down, rest. If fever sticks around >24 hours or breathing worsens, call your OB. Consider flu/COVID testing.
• 24 weeks, 101.5°F with burning urination and back pain: go to urgent care/ER today. This sounds like kidney infection. You’ll likely need antibiotics and maybe IV fluids.
• 34 weeks, 102°F with chills and decreased fetal movement: ER now. You need evaluation for infection and fetal monitoring.

Mini-FAQ:

• Can a fever harm my baby? Short, mild fevers usually don’t, especially if you treat them. High or prolonged fevers and the infections behind them can increase risk-so treat promptly and get checked when thresholds are met.
• Is Tylenol safe in pregnancy? Yes, when used as directed. ACOG supports acetaminophen for pain and fever during pregnancy. Use the lowest dose that works and keep total under 3,000 mg/day unless your clinician instructs otherwise.
• I accidentally took ibuprofen-now what? Don’t take more. Call your clinician, especially if you’re past 20 weeks. A single dose is unlikely to cause harm, but you should get personalized advice.
• How can I lower a fever without meds? Hydration, light clothing, a lukewarm shower/sponge bath, and a fan. These help, but don’t delay medication if your temp is at or above 100.4°F and you feel lousy.
• Are baths safe? Lukewarm baths can help; avoid hot tubs and very hot baths.
• Can I use cold/flu combo meds? Many are okay in later pregnancy, but ingredients vary. Avoid duplicates of acetaminophen. Ask your clinician or pharmacist to review the exact product and your trimester.

Pro tips and pitfalls:

• Write it down: temperature, time, symptoms, acetaminophen doses. It makes your clinician’s job easier and helps you spot trends.
• Don’t trust a single reading: confirm with a second measurement after 5 minutes.
• Combo meds hide acetaminophen: look for “APAP” or “acetaminophen” on the label so you don’t exceed the daily max.
• Pregnancy-specific red flags beat everything: UTI symptoms, contractions, decreased movement, or foul discharge move you up a level of care even if the temp isn’t sky-high.
• If you’re high risk (twins, diabetes, hypertension, immune issues), call earlier. Your threshold for evaluation is lower.

Next steps if things aren’t straightforward:

• No thermometer handy? Treat based on symptoms (chills, sweats, flushed skin) and get a thermometer today. Many drugstores carry reliable digital ones.
• It’s the weekend and your OB is closed: use the on-call line. If you can’t reach them and have any red flags, go to urgent care or the ER.
• You just traveled and have a fever: if you were in areas with malaria or dengue, go to the ER. Mention your travel up front.
• Fevers keep coming back: call your OB to check for UTI, sinusitis, or other infections that need antibiotics.
• Pain relief beyond acetaminophen: ask your clinician. There are pregnancy-safe options for cough, sore throat, and congestion, but timing and dosing matter.

Why trust these steps? They match how U.S. clinicians approach fever in pregnancy and align with guidance from the American College of Obstetricians and Gynecologists, the Centers for Disease Control and Prevention, and the U.S. Food and Drug Administration as of 2025. If anything here conflicts with your own clinician’s plan, go with their advice-they know your history and risks.