What causes color vision loss during pregnancy

Because of hormones, one of the leading causes of loss of color vision in pregnancy is Pituitary Adenomas. A large number of these tumors are undiagnosed but once the progesterone in a woman's body begins changing, the tumor changes and grows. These are usually removed surgically and with newer procedures, this can be done easily with causing very few problems with other brain areas. There are other problems that appear in women during pregnancy with loss of peripheral vision. If you are noticing either of these while pregnant, please go straight to your eye doctor and allow them to assess your condition. These are not things to sit and wait until you go see your OB the next time.
It is very common for a woman's vision to worsen while she is pregnant. Most eye doctors will do a quick refraction to check your vision and suggest an adjustment to your prescription if it will help you or ask if you just want to tough it out if you are close to the end of your pregnancy. If you wear contacts, this is a simple thing to just buy a new prescription box of lenses but if you wear glasses, it is a bit more expensive. Good luck and best wishes.