"Most of Trump's major immigration moves have been met with lawsuits. If the regulation leaves it to officers' discretion to ensure that B visas aren't used for birth tourism, it would be difficult to challenge in court, according to Lynden Melmed, an attorney and former chief counsel at U.S. Citizenship and Immigration Services.

"State Department officials have all the discretion in the world to deny people visas," said Sarah Pierce of the Migration Policy Institute. Foreign nationals who are outside the U.S. and have not yet received visas "don't have a lot of legal standing."
But specific restrictions that could keep out non-birth tourism visitors — such as pregnant women coming to the U.S. for business, etc. — would be legally questionable, according to Melmed and Gorsky."