how to read/interpret period tracker?

[handsome2]

i don't understand the period tracker.

googling result and the in-game period tracker use different term, like pms only mentioned in the game.

 

i have to get male sim to ask the female "about fertility" to get a simple idea.

there are many times, the male is busy, and i want to know about the female fertility, i can't really tell from period tracker.

 

what i want to know is whether current day is possible for the female to get pregnant based on her period cycle.

 

[Husk]

Try using the fertility test interation on a toilet with the Sim, should hopefully give you a clearer picture.