They have hair products that are more natural so less fumes and I believe ombra is the bulk of the hair but not the roots or like first two inches. If I'm thinking of the right thing I'd say go to it with a ventilated salon or home and enjoy your pretty look with Dr blessing :-)
I used to dye my hair all the time but IMO whatever touches your skin/scalp…you will absorb it. Also, you will no matter what, breathe in chemicals. I'd say it's best to wait. Do it after baby is born….take some time for yourself then! :)
I am not sure what an ombra is... All I know is my Dr told me that I can dye my hair all I want as long as I am in a well ventilated area. She said the bad thing for the baby is breathing in the chemicals in high concentration. Hope this helps