Progynova during breastfeeding.

Is progynova safe during breastfeeding? My period started last month , did not stop. Endo thickness was 18mm(Endo hyperplastic) . Gynec suggested to take meprate for 15days and on 5th day of cycle, told to take Cerazette. First five days bleeding was very heavy. After taking 5cerazette tablet, pelvis scan was done. Endo was 3mm , pcod, no polyps and fibroids. I have taken 7cerazette tablets and 13th day of my period. Lightly bleeding. So consulted gynec. She told my endo was thin., prescribed progynova 2mg (10days)along with Cerazette. My question is if I stop Cerazette, causes withdrawal bleeding. Again we can wait for next period right..? What is the reason for thickening of endo by using progynova? Will progynova affect my baby. I am breastfeeding and having 8month girl baby...