New visa rules aimed at women who come to the U.S. for "birth tourism" go into effect on Friday.

By imposing restrictions on tourist visas for pregnant women traveling to the U.S., the Trump administration aims to restrict women who come to the U.S. to give birth so their children can have U.S. citizenship.

According to the AP, "pregnant applicants will be denied a tourist visa unless they can prove they must come to the U.S. to give birth for medical reasons and have the money to pay for it." Otherwise, applicants need another "compelling" reason.

Visual cues such as appearing to be pregnant or listing "medical treatment" as travel reasons, could lead to questioning from consular officials, the AP reports.

These new visa rules will not apply to travelers coming from countries enrolled in the Visa Waiver Program. 

Citizens from those countries, which are mainly European and Asian countries, can come to the U.S. without a visa for temporary stays.

In a statement, White House Press Secretary Stephanie Grisham said, "Closing this glaring immigration loophole will combat these endemic abuses and ultimately protect the United States from the national security risks created by this practice."

According to the Los Angeles Times, officials have not been able to give detailed data on how many babies are born in the U.S. from "birth tourism" or concrete examples of the security risks it causes.

The LA Times also reports, immigrant advocates find these rules to be subjective, potentially discriminatory and open to abuse.

Birth tourism is a business that exists in the U.S. and other countries. It’s a business where, for a fee, companies give women the chance to travel to a country on a tourist visa, give birth, get medical care and citizenship and have a place to stay with their baby.