I am considering having corrective surgery for nearsightedness and astigmatism. I am 4 months pregnant and I want to go in for the evaluation in the next few weeks, and then schedule the surgery for soon after my delivery. Does pregnancy have any bearing on the evaluation?

You definitely need to wait until you deliver and are done nursing before having lasik. I usually tell my patients to wait 4 -6 months after that. The reason is that the shape of the cornea can change during pregnancy making it dificult to establish a stable prescription. This is probably due to hormonal changes but we are not sure.
Good Luck