During the eighth month of my pregnancy, my eye doctor said that i had very mild astigmatism. i have never been told that before. could it be pregnancy related or is it possible that i might have always had it?

Hard to tell : It could be hormone and fluids of pregnancy temporarily changing the vision. But it also could be something that you've had all along. Watch to see if it persists even 6 months after breastfeeding.

Unlikely: You likely always had this.

Possible: The hormones, esp late in pregnancy, that allow you to stretch to let your baby come out can affect the biomechanics of the cornea. That is the main reason that lasik is not recommended in pregnancy and nursing (a relative, not absolute, contraindication). Sometimes your cornea will resume its prepregnancy shape after you stop nursing, but not always. It is also possible that it was always there.

Could be either: If the astigmatism is very mild it is possible that you had it before pregnancy but you were not told about it or it was not previously measured. Astigmatism, especially mild in degree, is not uncommon in the last trimester. This change may reverse after delivery.