By Sonia Alvarado and Kirstie Perrotta, MPH, MotherToBaby California

By now you’ve likely heard about the fires taking place in Northern and Southern California. They have consumed thousands of acres of land, destroyed hundreds of homes and businesses, and killed humans and animals in their homes and cars. Smoke and ash have covered much of the state. The air quality has plummeted in the areas closest to the fires, but even miles away the air remains contaminated.

Unfortunately, wildfires are not unique to California, although this state is known for seasonal periods of wildfire risk. Due to climate change, experts predict that wildfires are likely to get worse. Wildfire season is no longer limited to a few months and appears to be extended to most of the year. So what do pregnant women need to know? Here are some commonly-asked questions we get at MotherToBaby about wildfire exposure during pregnancy:

Q. What is in the air from the fires?
A wildfire produces particulate matter (a combination of dirt, soil dust, pollens, molds, ashes, and soot), in addition to other chemicals. The wildfire smoke also contains carbon monoxide. The particulate matter can be different sizes. Particles less than 10 micrometers in diameter pose the greatest problems, because they can get deep into your lungs, and some may even enter your bloodstream. Exposure to smoke can cause you to experience difficulty breathing, irritation in the throat, and burning in the eyes. The closer you are to the fire, the more exposure you have, therefore, getting away from the fire as soon as possible is important.

Q. I’m pregnant. How does the particulate matter affect my pregnancy? What about the carbon monoxide?
Experts tell us that the smaller the particulate matter, the worse the effects on health, including difficulty breathing, aggravated asthma, and increased risk of heart attack and death due to respiratory and cardiovascular problems. Although we do not know enough about how exposure to particulates can impact a pregnancy, it makes sense for all individuals to take extra precautions to reduce their exposure.

Carbon monoxide is a gas that enters into the lungs and blood, and displaces oxygen to both mom and baby. The greater the exposure and the longer the exposure, the higher the risk. Studies suggest that there may be a higher chance of birth defects when a woman is exposed to carbon monoxide in the first trimester, but more studies are needed. Other studies have found an association between exposure to wildfire smoke and a decrease in baby’s birth weight. However this finding may be more related to the stress a woman experiences during a fire, or a combination of factors, than the actual smoke exposure. Again, more research is needed.

Q. I have asthma and I’m pregnant. Do I have added risks?
Yes. Studies in non-pregnant people tell us that exposure to particulate matter of 10 micrometers in diameter or less can make asthma symptoms worse. Pregnancy would not protect you and it may even put you at higher risk of having an asthma attack depending on how far along you are. See our fact sheet on asthma here:

Depending on your proximity to the fire zone, it may be difficult to get help if your symptoms worsen. First responders may be busy fighting the fires and evacuating residents, and may not get to you as quickly as you need. Emergency rooms may be overcrowded. For this reason, it is very important to always have your asthma medication with you so that in the event you have exposure to smoke that exacerbates your symptoms you can start to treat yourself. You also want to be in contact with your doctor and move away from the source of the wildfires as soon as possible.

Q. I’m pregnant and work outdoors. Do I need a mask?
The U.S. Environmental Protection Agency (EPA) has recommendations about what masks to use to protect against particulate matter entering the lungs. The goal is to prevent or reduce exposure as much as possible. If you work indoors, for the most part you are protected. If you work outdoors, you may want to consider using a mask that fits correctly and has two head straps to hold it in place. It should be labeled “particulate respirator” and it should have been tested or approved by the National Institute for Occupational Safety and Health (NIOSH). Learn more here. Because pregnancy can alter your lung function, women who are pregnant may have a harder time breathing to begin with. For that reason, it’s important to check in with your healthcare provider before using a particulate respirator.

If you are concerned about your work conditions, NIOSH offers a program called The Health Hazard Evaluation Program. This program helps employees learn whether health hazards are present at their workplace and recommends ways to reduce hazards and prevent work-related illness. Learn more here.

Q. I live about 50 miles from the wildfires. Do I still have to be concerned about being outdoors?
Depending on where you live and the direction of the wind, the air quality in your area may be poor due to the wildfire, even if the fire isn’t that close to you. Listen to the local health and environmental officials, and avoid exercising outdoors, gardening, or performing other activities that may cause you to exert yourself and inhale more of the particulates in the air. If you have any doubts, wait until the wildfires have been extinguished and the air quality is back to normal.

Q: Can fires cause other problems for moms-to-be?
Depending on weather conditions, wildfires can spread rapidly. The stress of having to make life and death decisions, or the decision to leave your home and decide what items to take with very short notice, all produce tremendous stress. It is absolutely normal to feel sad, stressed, anxious, or scared. In pregnancy, depending on how long the stress is present and the level of stress, it is possible that there could be impacts on the developing pregnancy, so anything you can do to try to reduce stress is always a good idea. Take a look at our fact sheet on stress for more information:

Q: I’m pregnant. What if I have to evacuate?
The best thing that you can do is to have a plan in place ahead of time. Make a checklist of items to take with you should you need to evacuate your home. Assemble an emergency supply kit and store it in a location where you can easily get to it, and create a family communication plan.

When the time comes to evacuate, stay calm. Be sure to bring any medications that you take on a daily basis (including your prenatal vitamins). Stay well hydrated, continue to eat, and rest as much as you can. If you have to check into a shelter, tell the staff there that you are pregnant so they can make any necessary accommodations.

While making it to your prenatal check-up is probably the last thing on your mind in the midst of an evacuation, it’s important that you continue to be seen by your doctor or midwife. Some women may be displaced from their homes for an extended period of time, however, it’s important to keep attending your prenatal care visits to make sure that baby is growing and developing properly.

If you’re close to your due date, check to make sure your hospital or birthing center is not in the mandatory evacuation zone. If it is located close to the fires, the staff and patients there may be asked to evacuate, and you may need to deliver at a different hospital. Knowing this information before you go into labor will reduce any unnecessary stress.

Q: What other steps can I take to minimize my exposure to smoke from a local fire?
Stay indoors when possible, and keep your windows and doors closed. If available, an air purifier can help with indoor air quality. If you have to drive somewhere, keep your windows rolled up and use the air conditioner to stay cool. If your car has a button that recirculates air internally, make sure it is turned on. Women who must venture outdoors may also consider purchasing a special face mask (called a N95 particulate respirator) that filters out harmful particulate matter. This mask should only be used under the direction of your healthcare provider. These are sold at many hardware stores and pharmacies, and can help minimize irritation from the smoke to your nose, throat, and lungs.

Q. I’m breastfeeding and I’m concerned about the wildfires in my area
Breastfeeding moms can also face challenges of their own when they have to evacuate their homes. When possible, follow the steps outlined above to reduce exposure to the wildfire smoke for both you and baby.

The benefits of breastfeeding are well known, and in most cases women are encouraged to continue to breastfeed their babies even when faced with an emergency like a fire. Nursing moms should focus on staying well hydrated and continue to feed baby on demand.

For moms that choose to pump breast milk, extra batteries may be something worth packing in your emergency supply kit in case the power goes out. For babies that are formula fed, it’s important to bring bottled water.

Q: Where can I learn more about fires currently happening and about air quality where I live?
CalFire provides general locations of major fires burning in California and The USDA Forest Service reports on large fires nationally. The EPA also has a website where you can check the air quality index in your local area:

About MotherToBaby
MotherToBaby is a service of the Organization of Teratology Information Specialists (OTIS), suggested resources by many agencies including the Centers for Disease Control and Prevention (CDC). If you have questions about exposures during pregnancy and breastfeeding, please call MotherToBaby toll-FREE at 866-626-6847 or try out MotherToBaby’s new text information service by texting questions to (855) 999-3525. You can also visit to browse a library of fact sheets about dozens of viruses, medications, vaccines, alcohol, diseases, or other exposures during pregnancy and breastfeeding or connect with all of our resources by downloading the new MotherToBaby free app, available on Android and iOS markets.