Pregnant women with thinning hair had to stop rogaine?

I am 12 weeks pregnant when i found out 6 weeks ago i stopped using rogaine. I am scared that i will start losing my hair in 4 months when the effects of rogaine wear off. Because i am pregnant do you think my high estrogen levels will allow my hair to stay on my head? i am concerned about this. a dermatologist said i most likely have andro alopecia, with low iron. this was 3 years ago. i started to experience hair loss when my 3rd son was 18 months old and i was still nursing. they thought post prtm hair loss was too long to last. i tried to get off rogaine a year and a half ago and after 4 months i started to shed so i started up again.
I am scared to be off of it.