It's called the Mikveh (hope I've spelled that right). They also have the Mikveh a little while after giving birth and after having sexual intercourse for the first time, possibly before and after. It's not quite as you have interpreted it, LR, nothing to do with being 'dirty', it's a ritual. Jewish girls love reaching the age to have Mikveh, it means a great deal. To be honest I think I would like it. There's more to it than meets the eye. Boys and men do too, different circumstances of course.
If you look on a Chassidic site (Chabad.org), you will find more info, LR It's very, very interesting. I think Owl is the only person with some Jewish ethnicity on here but he might not know much about the women's rituals (& it might not be him, sorry if I'm confusing him with someone else).
There was a TV series which has recently been repeated called, 'The Red Tent'; it's about Jacob's family (brother of Esau) and of course his son, Joseph (Leah's son), with the colourful coat - and his only daughter, Dinah (pronounced Dee-nah), who married an Egyptian. The bleeding is mentioned quite a bit, which is why it's called the 'Red' tent. Women's secrets which actually scared the men a little bit. Anyway, very good story. I also read it but missed the last TV episode, I'll try and catch it. I think you might like it it, is fictionalised but not entirely.
Jacob is played by the Scot actor, Iain Glen, which seems a bit silly considering all his sons are dark haired with dark beards, but he plays the part very well. His horrible Uncle Laban is played by Leigh Lawson, Twiggy's husband. He's good, doesn't matter he's not dark, he's older so grey haired.
Jacob has four wives whom he treats very well indeed; Leah the eldest, she has seven or eight children, only one girl, Dinah; second wife is one whom he loved very much, Rachel, she has two children, Joseph and Benjamin though Benjamin isn't really mentioned in the TV series. Jacob loves and treats them all well but the older boys are jealous of Joseph.