Fever in Pregnancy: When to Worry
Fever during pregnancy — when it's concerning, what to do, and safe treatment.
A temperature of 38°C or above counts as a fever. During pregnancy, your immune system works slightly differently to protect your baby, which means you can be more vulnerable to infections. Most fevers in pregnancy are caused by common illnesses such as colds, flu, or urinary tract infections — and most resolve without complications. That said, a high or persistent fever does warrant prompt attention, because sustained high temperatures in early pregnancy have been linked to an increased risk of certain birth defects.
What Temperature Is a Fever in Pregnancy?
Normal body temperature sits between 36°C and 37.2°C. A reading of 38°C or above is considered a fever. A temperature above 39°C is high and needs the same-day attention of your GP or, out of hours, NHS 111.
Use a digital thermometer for accuracy. Ear and forehead thermometers are convenient, but an oral or armpit reading can be more reliable if you're unsure.
Common Causes of Fever in Pregnancy
- Colds and flu — viral infections are the most common cause. Flu can be more severe during pregnancy; the NHS offers a free flu vaccine to all pregnant women, and it is safe at any stage.
- Urinary tract infections (UTIs) — UTIs are common in pregnancy and can quickly progress to a kidney infection (pyelonephritis) if left untreated. Always see your GP if you have a fever alongside pain when urinating, back pain, or cloudy urine.
- Stomach bugs — gastroenteritis can cause a mild fever alongside vomiting and diarrhoea. Focus on staying hydrated and contact your GP if symptoms are severe or lasting.
- COVID-19 and other respiratory infections — fever is a key symptom. Follow current NHS guidance and inform your midwife if you test positive.
Safe Ways to Bring a Fever Down
Paracetamol is the recommended pain and fever reliever in pregnancy. You can take the standard adult dose (up to four times in 24 hours) when needed — it is considered safe at all stages of pregnancy. Avoid ibuprofen during pregnancy unless specifically advised by your doctor.
Alongside paracetamol:
- Drink plenty of cool fluids — water, diluted fruit juice, or an oral rehydration drink.
- Wear light, loose clothing and avoid heavy duvets.
- Sponge your skin with lukewarm (not cold) water if you feel very hot.
- Rest as much as possible.
When to Seek Help
Contact your GP or midwife if:
- Your temperature reaches 38°C or above.
- A fever lasts more than 24–48 hours despite paracetamol.
- You have other symptoms such as a rash, difficulty breathing, pain passing urine, abdominal pain, or reduced fetal movement.
Call 111 if your GP is not available and you have a fever of 38°C or above in pregnancy.
Call 999 or go to A&E if:
- Your temperature is 39.5°C or above and not coming down with paracetamol.
- You have a severe headache, stiff neck, sensitivity to light, or a rash that does not fade when pressed (signs of meningitis).
- You feel extremely unwell, are confused, or cannot stay conscious.
Does Fever Harm the Baby?
A brief, mild fever treated promptly with paracetamol is unlikely to cause harm. Evidence suggests that very high fevers (above 39°C), particularly in the first trimester, may slightly increase the risk of certain birth defects — which is why it is important to treat fever early and not wait it out. If you are worried at any point, contact your midwife or GP rather than relying on self-care alone.
After the first trimester, the baby's major organs are already formed, so the risk profile changes — but fever can still cause discomfort and should still be managed and assessed promptly.
Frequently Asked Questions
Can a fever harm my baby in early pregnancy?
A very high fever (above 39°C) sustained over several days in the first trimester has been associated with a small increased risk of certain birth defects. However, most fevers in pregnancy are short-lived and treated effectively with paracetamol, which reduces the temperature before it can cause lasting harm. Contact your GP at 38°C or above so it can be assessed and treated quickly.
How do I treat a fever safely in pregnancy?
Take paracetamol at the standard adult dose, drink plenty of cool fluids, wear light clothing, and rest. Avoid ibuprofen during pregnancy. If your temperature does not come down within a few hours, or if it reaches 39°C or above, contact your GP or call 111.
Is it safe to take paracetamol for a fever when pregnant?
Yes — paracetamol is the recommended fever and pain reliever throughout pregnancy. Take it at the lowest effective dose for the shortest time needed, following the packet instructions. Do not take ibuprofen unless your doctor specifically advises it, as it is generally avoided during pregnancy.
Always speak to your midwife or GP for personalised advice about any symptoms during pregnancy.
Further reading:
This article is for informational purposes only and does not constitute medical advice.
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