According to the report, as of 2013, only the United States and Papua New Guinea didn’t require paid maternity leave.
The United States does require unpaid maternity leave, through the Family and Medical Leave Act. But even that law leaves a lot of workers ineligible for unpaid leave, either because their employer is too small to be covered by the law or because they haven’t worked for their firm for long enough.
(Hat tip to my colleague Trey Johnson on finding this updated ILO report.)