Overheating In Pregnancy: Signs, Causes, Risks And Prevention

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Hyperthermia or overheating during pregnancy can have adverse effects on you and the fetus. A core (internal) temperature rise of above 39¬°C (102°F) in a pregnant woman is considered harmful the fetus (1).  It is important to see a doctor if you have a fever, dehydration, heat exhaustion, or fatigue.

This MomJunction post explains the reasons behind the temperature rise during pregnancy, its impact, and ways to keep your body temperature under control.

Is Overheating During Pregnancy Common?

It may be normal for you to feel hot during pregnancy (2). As your baby grows, your body is likely to use more energy. In some cases, working in hot environments or specific work conditions could cause an increase in your core body temperature (3).

Extreme overheating is a cause of concern, and you need to be careful, especially when going out in the hot sun or while doing strenuous activities on a hot day.

How Do You Know If Your Body Is Overheated?

You may feel distinctly unwell while you feel the heat within your body. The possible symptoms of overheating are (4):

  1. Warm skin
  2. Headache
  3. Dizziness
  4. Nausea
  5. Muscle cramps

You may also be at a higher risk of developing heat exhaustion, heatstroke, and dehydration (5). You should see a doctor if you have these symptoms.

Causes Of Overheating In Pregnancy

There are limited studies on the causes of overheating during pregnancy. The possible reasons include:

  • Your blood volume increases by nearly 50% by the time you reach the 34th week of gestation (5). You might feel warmer as your blood vessels expand and move closer to the skin’s surface.
  • Your heart works harder and pumps 20% more blood by the time you reach your eighth week (5).
  • Your metabolic rate increases during pregnancy to create more energy for you and your unborn baby. This may also cause a spike in your body temperature (6).
  • The body heat shed by the growing fetus is usually absorbed by the mother. This primarily occurs in your third trimester. The increased skin temperature may, therefore, make you feel hot (7).

Some other general activities that could raise your core body temperature are (8):

  • Exercising in hot weather or for a prolonged period
  • Soaking in hot baths or saunas
  • High fever
  • Using heat pads or electric blankets

Possible Risks Of Overheating During Pregnancy

Overheating can increase the risk of certain eventualities.

  • According to a meta-analysis of 15 studies, excessive overheating in early pregnancy is associated with neural tube defects in babies (9).
  • Overheating in the first trimester is also likely to cause miscarriage (8), but this needs further research.
  • Also, the hot summer sun or weather could aggravate some conditions of pregnancy (10). It could
    • intensify the already raised body temperature.
    • accentuate edema (swelling) in the legs and feet.
    • stimulate melanocytes, causing chloasma (mask of pregnancy) (11).

How To Stay Cool During Pregnancy?

Here are some measures to keep your temperature in control, remain hydrated, and reduce exposure to heat during pregnancy (10).

  • Drink lots of water every day. Drinking at least eight cups of water might keep your body cool, treat dehydration, reduce water retention, and fight constipation.
  • Exposure to the sun can increase your internal body temperature. Avoid frequent exposure to the sun and always use a sunscreen or wear a hat before going out in the sun.
  • Take a lukewarm shower and not a cool one as it might chill your body, prompting it to create more heat.
  • You may run cold water over your arms and wrists for a quick cool-down. Applying a cold compress on your neck also works.
  • Wear comfortable and loose clothes that breath easy.
  • Carry a battery-operated fan or foldable fan to use when you feel overheated.
  • Brisk walking, water workouts (swimming), stationary bicycling, modified yoga, and Pilates are considered safe. Avoid hot yoga or hot Pilates as they may lead to overheating (12).
  • Exercise in the morning or evening, when the temperature is cooler.
  • Keep your bedroom cool by keeping the windows open in the evenings and closed during the daytime.
  • Place indoor plants in the house as they might cool the air and add freshness.
  • Cut down on caffeine as it is known to increase blood pressure and core body temperature.
  • Eat cold foods such as salads, fruits, and vegetables with high water content. Reduce the intake of spicy foods as they may increase the chances of overheating in the body.

These measures are likely to prevent you from overheating in pregnancy. You should see a doctor if you feel overheated or have a fever. Follow healthy habits, such as having a balanced diet, getting enough rest, de-stressing, and not smoking or drinking, to have a healthy pregnancy.


MomJunction's health articles are written after analyzing various scientific reports and assertions from expert authors and institutions. Our references (citations) consist of resources established by authorities in their respective fields. You can learn more about the authenticity of the information we present in our editorial policy.
1. Nicholas Ravanelli, et al.; Heat stress and fetal risk. Environmental limits for exercise and passive heat stress during pregnancy: a systematic review with best evidence synthesis; BMJ Journals (2017).
2. Pregnant this summer? Beating the heat means safety and comfort; The University of Alabama at Birmingham
3. REPRODUCTIVE HEALTH AND THE WORKPLACE; National Institute for Occupational Safety and Health; CDC
4. Summer heat brings special health risks for pregnant women; American Heart Association
5. Priya Soma-Pillay, et al.; Physiological changes in pregnancy; Cardiovascular Journal of Africa (2016).
6. Thomas W. Wang And Barbara S. Apgar; Exercise During Pregnancy; The American Academy of Family Physicians (1998).
7. The Third Trimester; The Johns Hopkins University
8. Pregnancy Precautions: FAQs; Brenner Children’s – Wake Forest Baptist Health
9. Moretti ME, et al.; Maternal hyperthermia and the risk for neural tube defects in offspring: systematic review and meta-analysis; Epidemiology (2005).
10. Keep Cool: Hot-Weather Tips for Pregnant Women; University of Rochester Medical Center
11. Hajira Basit, et al.; Melasma; StatPearls Publishing (2019).
12. Exercise During Pregnancy; American College of Obstetricians and Gynecologists