Workers hired to care for pregnant Chinese women who traveled to give birth on American soil are suing an alleged birth tourism center, citing unfair wages and working conditions.

In a lawsuit filed in Orange County Superior Court, six Chinese immigrant caregivers, including two from Orange County, say the Xin Xi Du Month Center forced them to work more than 70 hours a week while paying less than minimum wage and withholding overtime.

Southern California is home to a cottage industry for so-called birth tourists who travel here from China to give birth so their babies will have instant U.S. citizenship under the 14th Amendment.

For a growing Chinese middle class, U.S. citizenship means easier access to top universities, visa-free hassles for travel to many foreign countries, strong medical care, and the chance for the parents to apply for a green card once their child turns 21.

Pregnant women, or anyone else, can face federal charges if they use fraud or deception to obtain a visa, said Virginia Kice, a spokeswoman for U.S. Immigration and Customs Enforcement.

The Xin Xi Du Month Center, which has had bases in Irvine and Rowland Heights, is one of an unknown number of centers that cater to wealthy visitors from China, organizing transportation, medical care, housing, food service and shopping trips until the women give birth, said attorney Sam Wu, who is representing the caregivers.

Wu said it isn’t clear if the Xin Xi Du Month Center is currently operating. The lawsuit also names other individuals and businesses connected to the center. The center’s founders, Fiona Chan and Jeff Zhang, could not be reached for comment.

Wu said his clients were hired to provide transportation and all of the necessary care for the mothers, but they were required to work seven days a week for at least 10 hours a day with no breaks, hourly wage or overtime pay. Some were paid a flat rate of $100 a day, below California’s minimum wage, he said.

In some cases, the workers were tricked into signing leases for apartments for the pregnant women and were then left with the bills when the company stopped paying the rent, Wu said. A landlord took one of his clients to court for unpaid rent, he added.

“The employees are not highly educated, and they don’t speak English and the defendants were able to coerce them into signing the lease so their business would be more difficult to track,” Wu said. “They try to milk as much money out of it as they can.”

In 2015, authorities cracked down on the birth tourism industry with federal agents raiding three dozen homes, including some in Irvine. The agents were mostly pursuing suspects of visa fraud, or entering the country under false pretenses.

In the fallout, an Irvine-based immigration attorney, Kevin Liang, was sentenced to 21 months in prison for helping a Chinese national flee the U.S. after she was designated as a material witness in the criminal investigation. Another 10 Chinese nationals fled back to China and were charged with violating court orders to remain in the U.S. as material witnesses.