Arizona is HOT, especially in the summer. I knew this when I moved to Tucson almost a decade ago. Since then, I have had two pregnancies while living in Arizona. I was lucky that I didn’t have to spend the last few weeks of pregnancy and the first few weeks with my newborn in the summer heat.
Of course, Arizona isn’t the only place experiencing hot weather. In 2023 it was of the planet the hottest year on recordaccording to the National Oceanic and Atmospheric Administration. The temperature records already have it is broken in 2024, and extreme heat becomes more common. It’s important to understand how extreme heat can affect the health of the general population and for us at MotherToBaby, how high temperatures can specifically affect pregnant women. For more information on this topic, we reached out to Dr. Christina Han with our partner, the Society for Maternal-Fetal Medicine.
What is excessive heat?
Extreme heat is defined as “a period of high heat and humidity with temperatures above 90 degrees for at least two to three days.” (Ready.gov). According to Dr. Hahn, “excessive heat can lead to health problems for anyone, including heat rash, sunburn, heat cramps, heat exhaustion or heat stroke. These environmental changes also increase rates of violence and exposure to pollution. Certain groups of people are more likely to be affected by extreme heat, including people who are pregnant.”
What is hyperthermia?
Hyperthermia is an increase in body temperature that occurs when the body absorbs more heat than it releases. One of the most common causes of hyperthermia is heat stroke. Fever, extreme exercise, or using a hot tub or sauna can also increase the chance of hyperthermia.
Being pregnant in extreme heat can increase the chance of heat stroke, heat exhaustion, or other heat-related illness. In extreme heat, the body has to work harder to stay cool for two. When the body cannot cool down properly, there can be an increased chance of hyperthermia.
What are the concerns with overheating and pregnancy?
Studies have reported a small increased chance of neural tube defects (NTDs) in babies of people who had a high fever that lasted 24 hours or more before the 6th week of pregnancy. Some studies have reported a small increased chance of other birth defects when fever or hyperthermia occurs in early pregnancy, especially if the fever is untreated. Other studies have found no greater chance of birth defects when a person experiences hyperthermia early in pregnancy.
Pregnant women should also drink more water to avoid dehydration. Chronic dehydration can affect pregnancy outcomes. A study suggests that chronic dehydration may affect newborn weight, length, and head and chest circumference. Some studies have reported associations between high temperatures during pregnancy and a higher chance of preterm birth, low birth weight, and stillbirth.
What are some signs of heat-related illness?
Heat stroke: Body temperature of 103°F or higher. hot, red, dry or moist skin; headache; confusion, dizziness; nausea; fainting.
Heat exhaustion: Profuse sweating. cold, pale and soft skin. nausea/vomiting; dizziness, headache, muscle cramps. fatigue/weakness; fainting.
Heat-related illnesses can sometimes be an emergency. Anyone who believes they are experiencing a medical emergency should seek care immediately. For more information about when to seek medical help, visit the Centers for Disease Control and Prevention (CDC) page here: https://www.cdc.gov/niosh/topics/heatstress/heatrelillness.html.
Dr. Han also shared some general tips for dealing with overheating during pregnancy:
- Stay cool as much as possible, both indoors and outdoors
- Avoid peak sun hours if you must be outside
- Avoid or minimize strenuous activities
- Wear appropriate clothing such as hats and loose, light clothing
- Avoid alcohol and limit caffeine
- Wear sunscreen
- Be careful when participating in strenuous activities. make sure you take breaks, drink water and get plenty of rest.
- Check local news for heat warnings and health/safety advisories
Find more information from the CDC about preventing heat-related illness here: https://www.cdc.gov/extreme-heat/prevention/index.html.
The final advice of Dr. Han: Don’t forget to talk to your provider! “Your health care provider can help you find resources and ways to protect yourself and your family. “Managing exposure to extreme heat is important for everyone’s health, including those who are pregnant.”
MotherToBaby experts are also available to talk to you about exposures before or during pregnancy. Good luck staying cool out there!
