WASHINGTON — Five Texas Democratic members of Congress signed a letter demanding that the Department of Homeland Security explain why it has detained 525 pregnant women this year for immigration proceedings.

A 2016 policy states that Immigration and Customs Enforcement should only detain pregnant women in "extraordinary circumstances." But several women, including seven in Texas, describe receiving inadequate care — being denied extra blankets, food and prenatal resources — and three suffered miscarriages, according to an American Civil Liberties Union memo referenced in the letter.

"Attorneys and advocates are reporting a marked increase in the number of pregnant women with serious medical concerns coming to their attention in recent months, and a seeming shift in the agency's willingness to release pregnant women once the pregnancy is identified," according to the letter.

Democratic Reps. Beto O'Rourke of El Paso, Sheila Jackson Lee of Houston, Lloyd Doggett of San Antonio, Filemon Vela of Brownsville and Vicente Gonzalez of McAllen were among 70 members of Congress who signed it. The letter demands numbers in the next 30 days on how many women are in detention and for how long they have been there as well as details on how the "extraordinary circumstances" rule is applied.

"Texas leads the country in the rate of maternal mortality right now, so we should be acutely sensitive," O'Rourke told The Dallas Morning News. In addition to improving health outcomes, ensuring pregnant detainees are able to stay with family members or community volunteers would save taxpayer dollars, he added.

He cited instances in his home district of El Paso when DHS released immigrant mothers into the community.

"It didn't harm our safety or our security in the community, so there's no security risk in ensuring that these women are able to be with family or get the needed medical help," he said.

The letter comes after several controversial immigration lawsuits filed against federal immigration agencies. The ACLU sued Customs and Border Protection and the Office of Refugee Resettlement last week for detaining a 10-year-old girl with cerebral palsy apprehended on her way to emergency surgery. She was released Friday.

A pregnant minor sued the ORR and parent agency the Department of Health and Human Services last month for refusing to allow her to get an abortion while in custody.

Sarah Rodriguez, an ICE spokeswoman, said that all female detainees up to age 56 are offered pregnancy tests.

"ICE detention facilities provide on-site prenatal care and education, as well as remote access to specialists for pregnant women who remain in custody," she said. "The current policy notes particularly that women who are confirmed to be pregnant will not be required to wear radio frequency or global positioning system monitors as a part of ATD program. Detention resources are prioritized based upon potential danger to the community and risk of flight."

An ICE official stressed that agents could determine when "extraordinary circumstances" warrant detention, and conducted case-by-case reviews of all pregnant or non-pregnant detainees. As of Sept. 13, ICE had 33 women who were confirmed to be pregnant in custody, per agency statistics.

But Jackson Lee said that when she visited the border a few weeks ago, women were facing serious challenges in detention.

"Even though the attendants were well meaning, there were women sitting on the floors, there were children sitting on the floors," she said. "They can test for measles, but the idea is whether these women are taken care of and treated, and whether or not they actually need to be held, whether there is not a more suitable legal arrangement that can be established for pregnant women."

Vela said that he was concerned but not surprised by the alleged ICE actions due to President Donald Trump's campaign remarks and executive orders against immigration.

"These agents are following orders and these orders come straight from the top," he said. "It's no surprise to me; I knew from the very beginning when Trump was elected and when he used the executive orders on all sorts of immigration issues that we were going to see a downward spiral in terms of immigrant rights."