After five days of an unrelenting firestorm in Los Angeles County, medical experts are warning that the area’s smoke levels pose unique risks to expectant pregnant people and their unborn children.

So what should pregnant L.A. residents do?

First and foremost, doctors say they should follow local emergency guidance around evacuation, according to Dr. Allison Bryant, a maternal fetal medicine specialist at Mass General Hospital who chairs the American College of OB/GYN (ACOG) Committee on obstetric care practice.

Beyond monitoring evacuation orders, Bryant suggested following Centers for Disease Control and Prevention guidelines that recommend pregnant people should stay inside as much as possible with windows and doors closed, use HVAC systems with filters or portable air purifiers, and wear N95 masks if outdoor exposure is unavoidable. They should maintain their prenatal care schedule as much as possible and update their delivery plans if evacuation becomes necessary.

Emergency preparedness is also crucial. The CDC recommends keeping a seven- to 10-day supply of prescription medicines and prenatal vitamins ready. That supply can go in a go bag with essential items, including clothes, medical records and insurance information.

The CDC advice closely aligns with new guidance on preparing for disasters that ACOG released this month, specifically focused on helping pregnant individuals navigate emergency situations. While many precautions mirror general public health guidance, pregnant people face additional considerations around maintaining prenatal care and preparing for delivery.

“What’s different about pregnant individuals is that we know that they’re going to need healthcare in the not-too-distant future,” Bryant said.

Research suggests that babies born to mothers exposed to wildfires may be smaller than average, with the effect potentially strongest in later pregnancy, Bryant said. But the risks go beyond just smoke exposure. Pregnancy itself makes people more physically vulnerable, with changes to breathing patterns, heart function and mucus membranes that can intensify the effects of smoke and air pollution.

“During pregnancy, everyone’s mucus membranes — the lining of your nose and mouth — are more active and plump,” Bryant said.

This natural increase in congestion means pregnant people may experience more severe symptoms from smoke exposure than others in their household.

Although the risks don’t vary dramatically by trimester, pregnancy itself makes people more vulnerable to respiratory challenges, according to Dr. Joseph Ouzounian, chair of obstetrics and gynecology at USC’s Keck School of Medicine.

“Pregnant people will breathe more rapidly than non-pregnant people,” he said. “The heart and cardiovascular system are working harder because, to some extent, they’re supporting two lives instead of one.”

Short-term exposure of a few days is typically not dangerous if reasonable precautions like wearing N95 masks are taken, Ouzounian said. However, longer exposure requires more decisive action. Prolonged exposure to environmental toxins could affect a fetus’ development.

With winds expected to intensify again Sunday and potentially reach 50 to 60 mph in mountains and foothills by Tuesday, relief from poor air quality may not come soon. Following public health guidelines should be sufficient for most, but Ouzounian said that those who aren’t close to delivery and can’t maintain adequate air quality at home may want to consider temporary relocation.

“If the exposure is going to be more than a few days, then you have to start thinking about either finding somewhere where the air is better or staying indoors with air filters or air purifiers,” he said.

Some of Ouzounian’s patients are leaving town, including a woman who lived in a mandatory evacuation zone and temporarily relocated to Orange County, where she has already found a new doctor. While most of his patients are staying put, he said that if the fires persist or worsen over the next couple of weeks, he expects more patients will consider transferring their care.

Dr. Christina Han, a professor of clinical obstetrics and gynecology at UCLA’s David Geffen School of Medicine, also has patients who are planning to relocate to Arizona, San Diego and Northern California. This is especially true for those who have lost their homes and know they won’t be able to rebuild within the time frame of their pregnancy.

“Everybody has a different scenario right now, so we kind of have to just use shared decision-making to kind of go through that calculus with them,” Han said.

She emphasizes that patients should consult their OB-GYN before relocating, because doctors can help connect patients with care in their new location.

“It’s really hard to find an OB last minute, so they should try to utilize their OB-GYN’s network,” she said. “OB-GYNs have a very tight network, so many of us know where other docs are around the country and can potentially reach out to ask for help.”

Although research on wildfire exposure’s effects on pregnancy isn’t definitive, Han stressed that pregnant people following simple precautions are going to be fine. Her most crucial advice?

“Wearing [an N95] mask is really important,” Han said, “more important probably than taking prenatal vitamins at the current time.”