Hi @gamora24
As John suggests, I encourage you to read the posts in this discussion about oral lichen planus. Members there share effective ways of preventing and managing flare ups.
Groups > Autoimmune Diseases > Erosive oral lichen planus
— https://connect.mayoclinic.org/discussion/erosive-oral-lichen-planus/

You ask a unique question about oral lichen planus related to pregnancy and hormones. I'm tagging members @mrmie @dreamer60 @alpaca @loli and @wisgrama. It must be a relief that the lichen planus has disappeared during your pregnancy, but I can understand your concern that it may come back as hormones change after birth and/or breastfeeding. I wonder if anyone else has experienced changes specific to hormonal changes during pregnancy or even related to menopause.

Gamora, Have you discussed your hypothesis with your doctor?