7.1.3. Form the shape of a drop over your head using both hands — and you’ve created the ‘period out’ hand signal. By using it, a female football player can signal to the referee that she needs to leave the pitch due to her period. No interruptions needed; the play continues as usual. With the referee’s approval, the player can re-join the game. Only if a goalkeeper shows the ‘period out’ hand signal, the game is paused briefly.
Currently, there is no official regulation on this matter by any football association. And that needs to change.