Body Temperature Changes in Early Pregnancy

Feeling warmer than usual is a common early pregnancy symptom, and it can catch you off guard if you're not expecting it. Understanding why your body temperature changes — and crucially, what's normal versus what needs attention — helps you feel more in control in those early weeks.

Table of Contents

1. Why You Feel Hotter
2. Normal Warmth vs. Fever: What's the Difference?
3. When to Seek Help
4. FAQ

Why You Feel Hotter

Progesterone — After ovulation, progesterone levels rise sharply. If the egg is fertilised, progesterone continues to climb throughout the first trimester. This hormone raises your basal body temperature (BBT) — the temperature your body sits at when fully at rest. This is why BBT charting can be used to detect pregnancy: the temperature stays elevated rather than dropping before a period. You may notice you feel consistently warmer, sweat more easily, or find rooms that used to feel comfortable now feel stifling.

Increased blood volume and circulation — Your body begins increasing its blood volume very early in pregnancy to support the growing pregnancy and, eventually, the placenta. This increased circulation means more blood is flowing closer to the surface of your skin, which can make you feel flushed and warm, particularly in your face and chest.

Both of these effects are completely normal and are not a sign that anything is wrong. Many women describe feeling like they've "turned the heating up" — even in cool weather. Night sweats and waking up too hot are also common in the first trimester.

Normal Warmth vs. Fever: What's the Difference?

• Feeling warm or flushed: your body feels warmer to you or others, but your actual temperature is not significantly raised when measured. This is the progesterone effect and increased circulation — entirely normal.
• Fever: your measured body temperature is 38°C or above. A fever means your body is responding to an infection or illness. This is not a normal pregnancy symptom and needs to be taken seriously.

A normal basal body temperature in early pregnancy is slightly higher than your pre-pregnancy baseline — but it should still be well below 38°C. If you're unsure, take your temperature with a reliable thermometer. A reading below 37.5°C alongside a general feeling of warmth is nearly always just normal pregnancy physiology.

When to Seek Help

• Your temperature is 38°C or above, even if you feel otherwise well
• You have a fever alongside other symptoms such as painful urination (possible UTI or kidney infection), abdominal pain, a rash, or feeling very unwell
• You have been in contact with someone with a serious infection (such as chickenpox, if you're not immune)

A fever in early pregnancy is worth assessing promptly because high temperatures — particularly if sustained — can affect early fetal development. Your GP may want to identify and treat the underlying cause. Paracetamol is considered safe to use during pregnancy to bring down a fever while awaiting advice, though you should always read the packaging and check with a pharmacist or GP about dosage.

Avoid ibuprofen during pregnancy unless specifically told otherwise by a doctor.

If you feel very unwell, have a very high temperature, or have difficulty breathing alongside a fever, call 111 or seek urgent medical attention.

Frequently Asked Questions

Yes. Feeling warmer than usual is a very common early pregnancy symptom, caused by rising progesterone levels and increased blood circulation. You may feel flushed, sweat more easily, or struggle to get comfortable in bed. This is normal and usually continues throughout the first trimester. It does not mean anything is wrong with you or your pregnancy.

Can a fever harm my baby in early pregnancy?

A high fever (38°C or above) in early pregnancy is something to take seriously and get checked out. While feeling warm is normal, an actual fever signals that your body is fighting an infection, and the underlying cause needs to be treated. If your temperature reaches 38°C or higher, contact your GP as soon as possible. Paracetamol can help bring the temperature down safely in the meantime.

How can I manage feeling too hot in early pregnancy?

Keep rooms cool and well-ventilated, wear light and breathable fabrics, stay well hydrated, use a fan at night, and take cool (not cold) showers if needed. Avoid getting overheated in saunas, hot tubs, or very hot baths, as sustained high external heat can raise your core temperature in ways that feeling warm from hormones does not.

Always speak to your midwife or GP if you are concerned about your temperature or any symptoms during pregnancy.

Further reading:

• NHS — Common pregnancy symptoms