Researchers with the University of California, San Francisco, are calling on city and county officials to prioritize all homeless, pregnant women for shelter beds and transitional or subsidized housing.

Homeless women in San Francisco must currently have a serious medical condition or wait until their third trimester before they’re considered “high risk” under city and county housing policy, according to according to a San Francisco State University report conducted in partnership with UCSF, Homeless Prenatal Program, SF Black Infant Health, the Y of San Francisco and Women’s Community Clinic.

That’s too late to provide them with the stability they need for a healthy pregnancy, and to reduce their risk of preterm birth, researchers said.

“We believe that all pregnant women who are unstably housed are high risk and should be considered a priority for housing resources,” said Shanell Williams, director of community engagement with the UCSF California Preterm Birth Initiative, a research partnership that includes community organizations and the San Francisco Department of Public Health. “We want to see a change.”

Compared to pregnant women who live in standard housing, homeless pregnant women in San Francisco experience more than double the rate of preterm birth. About 1 in 5 pregnant women who are homeless give birth prematurely, according to research findings cited in the UCSF report.

The stress of homelessness and lack of access to prenatal care contribute to these women’s higher risk for preterm birth, said Sabra Bell, one of the researchers. Some may find themselves evicted from single-occupancy hotel rooms because they’re pregnant, or living doubled-up with other families in unsanitary and unsafe living conditions, she said.

Bell and nine other community researchers conducted interviews with 84 women of color who had experienced housing instability and pregnancy. She said some of the stories she heard were shocking.

“Some people couldn’t afford food. Some people shared housing with other people who ate their food, or they could only afford processed food,” Bell said. “It brings tremendous stress.”

African American and Latina women are disproportionately impacted by preterm birth, as well as other problems such as housing and food insecurity, said Williams.

“They are experiencing multiple levels of trauma,” she said. “It’s really a racial issue that we’re seeing in San Francisco, including access to the kind of care and resources they need to have a healthy pregnancy.”

Williams and Bell said UCSF researchers plan to meet with local department heads and elected officials in the coming weeks to discuss their findings and request for a policy change.

Jonathan Fuchs, who helped lead the research at UCSF and is also a senior official with the San Francisco Department of Public Health, said he hopes other government officials will take a serious look at the findings and consider reevaluating the current policy on housing.

Preterm birth is a major public health issue, he said, contributing to infant death rates and also long-term physical and mental health problems in children born prematurely.

“I think the results of this study really come at an important time,” he said. “Given the incredible levels of stress being homeless or unstably house can have on the pregnancy, it’s critical that we reevaluate how we approach (housing support) for pregnant women.”