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Pregnancy and Reproductive Health​

Safe Pregnancies in Extreme HeatPregnant and keeping cool outdoors

What is Extreme Heat?

Extreme heat is two or more days and nights of excessively hot weather, with temperatures above usual for your region. In California, extreme heat is most common in the summer months but can occur April through October.1

Climate change  is making extreme heat worse. Hot days are getting hotter and longer than they were in the past. Extreme heat can harm you and your developing baby, so it’s important to take precautions to stay safe.

How Does Extreme Heat Impact Me and My Baby?

Pregnant people are more likely to get heat-related illness than people who are not pregnant. This is because:

  • Your body works harder to keep both you and your baby cool.
  • You are more likely to become dehydrated, which makes sweating less effective.

Even if you are generally healthy, you can experience heat-related illness within one hour of being in extreme heat. Ongoing exposure to extreme heat is also risky. Being in high temperatures that your body is not used to make it hard for your body to cope with the sudden increase in heat exposure.2

Extreme heat may also increase your risk of dangerously high blood pressure, seizures, and other serious complications during pregnancy.3

When you overheat, oxygen and blood flow to your baby decreases, which can harm their development. Research shows that heat exposure at any point in pregnancy may increase the risk for the following: 4

The risk for health problems for you and your baby increases as temperatures and heat exposure increases. With that said, even as little as one day of hotter temperatures may increase risk. 5

Extreme Heat Risks aren’t Equal

While being in extreme heat is dangerous for everyone, you have a higher risk if any of the following are true for you: 6

  • Work in a hot environment (outdoors, restaurant kitchen, warehouse, or factory).

  • Live in an area with limited shade and green spaces and/or where air pollution is bad.

  • Don’t have or use air conditioning at home or can’t easily get to an air-conditioned public space (like a library or shopping center).

  • Have a high-risk pregnancy or are already having pregnancy complications.

  • Live with a chronic health condition, including behavioral or mental health conditions.

  • Are under 18 years old.

  • Are taking certain medications  (like antidepressants, beta-blockers, and other heart medications) that can interfere with the body’s internal temperature or impair sweating.

Keeping You and Your Baby Safe from Extreme Heat

There are several ways you can stay safe when it’s hot outside. The following list offers protective actions you can take to keep you and your baby safe from extreme heat. You can also use Get Ready tool  to make a personal extreme heat plan.

Are you a health care provider? 

Check out the CDC’s Clinical Guidance  to help talk with your pregnant patients about the dangers of extreme heat and ways to stay safe. The CDC has pre-made patient education materials for you to use!

Do What You Can to Prepare in Advance

  • Check the Heat Risk  forecast daily during warm months. Take protective action when HeatRisk is orange or higher. CDPH’s Heat Risk Grid  includes protective actions to take for each HeatRisk level. The Heat Risk is also available in Spanish . 
  • Know the signs of heat illnesses! It’s easy to confuse some with common pregnancy symptoms.

    • Heavy sweating

    • Being very thirsty

    • Nausea or vomiting

    • Dark-colored urine

    • Muscle cramps

    • Fast heart rate or fast breathing

    • Headaches or dizziness

    • Increasing Braxton Hicks contractions or cramping

    • Dry skin*

    • Confusion*

    • Seizures*

    • High fever*

    • Slurred Speech*

    *Could be symptoms of heat stroke requiring immediate medical attention.

  • Prep your home for heat

    • Get blackout drapes or shades for windows.

    • Use window reflectors that reflect heat back outside.

    • Use weatherstrips and/or add insulation to doors and windows to keep the heat out.

    Find Assistance

    Use this Find Assistance page  to learn about programs that may help you with cooling costs or energy-saving home repairs.

Do What You Can During Extreme Heat

  • Stay Hydrated

    • Drink more water than usual .

    • Eat fruits and vegetables with high water content.

    • Avoid sugary and caffeine-rich drinks to prevent dehydration. Check out Reth​ink your Drink! 

  • Designate a Cool Room

    • Choose a room that can be closed off from the rest of the home. Try to pick a room that:

      • Is fully shaded by a tree, awning, or patio.

      • Is less likely to have heat enter through windows, walls, or ceilings.

      • Faces north or northeast or is located on a lower level.

    • While in your cool room,

      • Reduce the use of electronics that produce heat (TVs and computers). ​

      • Wear light and loose clothing and avoid wearing black since the color absorbs heat.

      • Keep windows covered.

      • Use frozen items (like wet cloths or bags of frozen veggies) to put on your neck, wrists, or head.

      • Use a fan if the indoor air temperature is less than 90 degrees F.

      Important Reminders about Fans!

      • Setting your ceiling fan to rotate counterclockwise will push air down. Check to see if your ceiling fan can do this.

      • Electric fans do not prevent heat-related illnesses when temperatures are above 90 degrees F. 

  • Staying Cool When You Sleep. Getting a good night’s sleep is crucial during pregnancy, but it can be tough when you’re feeling too hot. To help with this, try to:

    • Wear loose pajamas.

    • Use a single sheet instead of a heavy comforter.

    • Use frozen items (like wet cloths or bags of frozen veggies) to put on your neck, wrists, or head.

    • Consider sleeping separately from your partner on the hottest nights.

  • Seek Support

    • Ask family, friends, or your doula to check in on you daily when it’s hot.

    • Extreme heat can impact mental health. Learn about mental health resources available in your community and from your healthcare provider.

    • Some medications can make the body more vulnerable to heat, so let your healthcare provider know that you live or work in a hot place.

    • Call your healthcare provider if you’re feeling too hot.

    • Use worker protections provided by law. You’re entitled to reasonable accommodations (like more water and rest breaks) to stay safe at work.

  • Do you have Medi-Cal? 

    Doula services are now a covered benefit. Learn more!  

Access Community Resources!

  • Call 211  for essential services to help you beat the heat, like cooling centers and public pools.

  • Find Your Local Library  if you need a public space with air conditioning.

  • Call your utility provider to see if they have programs to help residents weatherize their homes or reduce energy costs. 

Extreme Heat Guidance for the Entire Family

References

  1. Extreme Heat Events. California Office of Environmental Health Hazard Assessment. Extreme heat events | OEHHA (ca.gov)

  2. Kuehn L, McCormick S. Heat Exposure and Maternal Health in the Face of Climate Change. Int J Environ Res Public Health. 2017 Jul 29;14(8):853. doi: 10.3390/ijerph14080853. PMID: 28758917; PMCID: PMC5580557.

  3. Gulcan Cil and Trudy Ann Cameron. “Potential Climate Change Health Risks from Increases in Heat Waves: Abnormal Birth Outcomes and Adverse Maternal Health Conditions,” Risk Analysis, November 2017, doi:10.1111/risa.12767

  4. Bruce Bekkar, Susan Pacheco, Rupa Basu, and Nathaniel DeNicola. “Association of Air Pollution and Heat Exposure with Preterm Birth, Low Birth Weight, and Stillbirth in the U.S.” JAMA Network Open, June 18, 2020, doi:10.1001/jamanetworkopen.2020.8243

  5. Pregnancy and Heat Clinical Guidance. Centers for Disease Control and Prevention. Updated April 22, 2024. Clinical Guidance for Heat and Pregnancy (cdc.gov)

  6. Pregnancy and Heat. California Office of Environmental Health Hazard Assessment Pregnancy and Heat — Protect yourself and your baby - OEHHA (ca.gov)

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