A dilated pupil is not something to take lightly. The cause can be very minor to severe. If you are not 100% happy with what you have been told then it is always advisable to see your GP, an ophthalmologist or your Neuro to get a second opinion. Even if they give you the same diagnosis you at least will have the peace of mind of having qualified people answer the questions you need answers to.
Good luck and many congratulations on the pregnancy! Sorry not to be of more help.