In a clear attempt to curb immigration, the White House has decided to roll out a set of new visa regulations aimed at restricting "birth tourism," a term used to describe the practice of pregnant women travelling to the U.S. for the purpose of giving birth and obtaining citizenship for their children.

The rules have not yet been publicized until Thursday morning in Eastern Time, but what is now known is that visa applicants who are deemed by consular officers as planning to give birth in U.S. soil will now be treated like other foreigners seeking for medical treatment in the U.S., which means they will have to prove they are going for medical treatment and they have money to pay for it. The rules will take effect on Friday.

Restricting all forms of immigration is one of the signature policies the Trump administration has been pushing for, but such efforts, especially the ones designed to end "birth tourism," have been proven difficult at the operational level.

Although regulating tourist visas for pregnant women is one way to get at the issue, it does raise questions about how officers would determine whether a woman is pregnant to begin with, and whether a woman could get turned away by border officers who suspect she may be just by looking at her.

Consular officers don't have to ask during visa interviews whether a woman is pregnant or intends to become so. But they would have to determine whether a visa applicant would be coming to the U.S. primarily to give birth.

Birth tourism is a lucrative business in both the U.S. and abroad. American companies take out advertisements and charge up to 80,000 U.S. dollars to facilitate the practice, offering hotel rooms and medical care. Many of the women travel from Russia and China to give birth in the U.S. The U.S. has been cracking down on the practice since before Trump took office. 

The practice of sojourning to the U.S. to give birth is fundamentally legal, although there are scattered cases of authorities arresting operators of birth tourism agencies for visa fraud or tax evasion. And women are often honest about their intentions when applying for visas and even show signed contracts with doctors and hospitals.

There are no figures on how many foreign women travel to the U.S. specifically to give birth. The Center for Immigration Studies, a group that advocates for stricter immigration laws, estimated that in 2012, about 36,000 foreign-born women gave birth in the U.S., then left the country.

The draft rule is "intended to address the national security and law enforcement risks associated with birth tourism, including criminal activity associated with the birth tourism industry," a State Department spokesperson said.